I couldn't finish the show, so perhaps I lost some of the context, however here are the reasons I got so far (and why I couldn't go further)

The good: acting was excellent, particularly on the part of the girl, who is an actress well into her 20s but managed to portray an adolescent girl growing into herself in a very convincing way. The script also portrays the frustrations of a teenager who is trying to establish self-authority and identity conflicting with parents who don't always know how to interact or guide an offspring going through a transitional period of development. I particularly like how the girl, who is not unusually talented, is not intimidated by hardship or previous failures and is willing and capable of putting in the work to excel. She isn't afraid to ask for help, isn't afraid to admit her weaknesses, and isn't afraid to face her own character flaws consciously and deliberately in order to improve herself as a person. This is a well-written character whose personality would be laudable in real life, and this is what earns her the respect of her genius male friend; a lot of shows have a girl who is measurably dumber than the guy, and it's hard for me to accept why he would respect her when she's inferior to him in every way. I fully believe that in this show, the male lead genuinely admires the female lead for her resilience and character.

Their relationship in the beginning is very beautiful and very warm, with both clearly caring about each other. It almost runs a little saccharine, and I'm sure it does for some, but I personally wasn't looking for a show that depicts the sharp edges of our world, so I'm actually fine with this.

The bad:
SPOILER

In a way, the title gives it away. This is a show about secrets, and there are subtle secrets tucked into the foundation of this show. However, I'd argue that there isn't anything particularly good about the fact that these are secrets, nor the way the show addresses them. One of the main conflicts, as stated above, is the girl's relationship with her parents. Her mother, particularly, is a well-intentioned but thick-headed woman who isn't entirely able to see past her own assumptions, however while the method of communication is often a problem between teenagers and their parents and I'm totally fine with this, I don't like how the show seems to imply that the female lead is right to keep certain secrets. The fact is, teenagers are rash, inexperienced, and shortsighted. Yes, they should be allowed to make their own decisions, but this should be done with guidance. The problem is not that they make their own decisions, it's how. Even adults need counsel on choices in life. Heeding advice does not mean you allowed someone else to make the decision for you; you are allowing yourself to make a decision with context that happens to include that advice. This show celebrates how the girl defies her parents to make her own decisions in major, stands up for herself by never discussing her thought processes leading up to these decisions because they are her "secrets", and winds up revising an extra year just to get into the same university as her love interest, and goes as far as choosing a major she's not interested in nor particularly good at just because the male lead is in it. This has worked in real life precisely NEVER. It's one thing when she persevered in subjects she was weak at when she was in high school and these were necessary milestones shared by everyone at her stage; it's another when this is supposed to direct her future career. She even cries in one scene because she feels so exhausted trying to be a good match for the male lead, and instead of having him reassure her that he would love and respect her even if she chose her own career path, they could make it work and utilize each other's different talents to make a synergistic whole, the show has him try to move away from her to lessen the pressure on her, and then has her fight to win him back by proving that she can still excel in something she doesn't like as long as she puts her mind to it…and also devotes more hours and effort. Perhaps later in the show she might realize how dumb she is being and come to her senses, but given that all of her poor decisions have been rewarded for so many episodes already, I highly doubt it. I don't even care that she does luck out and her poor choices wind up being fruitful, because that happens, but the show seems bizarrely lacking in self-awareness in this case. There is also nothing healthy about her keeping her secrets, nor is there a healthy resolution to those secrets, and yet the show treats this like it is a beautiful, praiseworthy attribute.

The adults are a little more clueless than I'm used to. Early on, the show is set in a rather prestigious high school. I also went to a selective high school that required passing an entrance exam, though not in China, and from my recollection, the teachers in the school were much less suspicious of students compared to the teachers in this show. In the show, the teachers are always scolding students for slacking, falling asleep in class, reprimanding them for not taking their exams seriously. In my high school, the students were generally diligent and the teachers knew. Prestigious schools tend to have a culture among the student body, and students are usually well-behaved and studious at baseline, so teachers adjust accordingly. In this show, everyone is constantly concluding that the students are being lazy. It seems like the show was written by someone who has only been to a normal high school with delinquents and mediocre students and has no idea that such a model doesn't fit the school this show is supposed to be in. The show also doesn't seem to think highly of the adults; at one point the male lead sneaks out after curfew at the high school dorm (which is confusing to me because this isn't a boarding school as far as I know, but I don't know how it works in China) and when he comes back, he refuses to tell his supervising teacher where he went and what he did. He got punished, and the show depicts this like the teacher is judgmental and unfair; how is this judgmental and unfair? The teacher is responsible for all these teenage brats; what if the student were killed after he snuck out? Of course he should be punished. I realize a teenager might complain about this treatment, but the show should know better. It's weird how this show lacks insight when it otherwise seems pretty aware of other aspects of the teenage condition.

The love in this show starts off wholesome and sweet and I had true admiration for the characters for many episodes. It just a shame that the message becomes harmful in the middle. There is nothing to celebrate about losing yourself to love. That's how disasters happen in real life. Truly beautiful love should be the kind that nurtures and improves the kind of person you would have become on your own, and inspires you to make life decisions that make you happier and healthier than you would have
made without that love. By its nature, a romantic relationship requires sacrifice, so the benefits you reap need to be greater than what you give up in order for it to be worthwhile. If your relationship inspires you to do something that will exhaust you all the time in order to keep up, or makes you feel like you need to do something you don't like in order to make yourself worthy of your partner, that's not right. To be fair, the male lead does nothing to force or even encourage the female lead to do these airheaded stunts, but still, she's not doing this right and the show has had no acknowledgment of that. 8/10, being generous because I didn't finish, but I can't. Sorry, show. You had something great going at first.