My biggest problem with this book was the hole between what the MC told me how she was and how she acted, and how she actually said and did. There was quite a big difference between the Lara Jean narrating (16 year old acting like a nine-year-old) and the Lara Jean in the dialogues (who showed innocence but it was snarky and sassy too). 
 Beside that, the way she thinks sometimes is too old-fashioned to be believable and some of her remarks (in the narration) were sexist to the point of wanting to slap her (I think, the author tried to correct this in the second book with some dialogues/monologues by the women in Lara Jean's life, but it didn't work out very good IMO. They sounded a bit like lectures and felt forced, like the author was trying to teach a lesson to LJ and the reader). But on the other side, she was quite bold, because if she really was that old-fashioned she would have never ever taken the initiative with Peter (she was almost always the one kissing him and not the other way around). This of course confirms the contradiction between Lara Jean speaking, Lara Jean acting and Lara Jean thinking... 
 I did like Peter, but he also was showed by LJ's narration as a egocentric jerk which left me thinking whether Peter was really that way or LJ just was seeing thim that way. 
 The other thing that got me on my nerves pretty often in this book was everybody's over-protectiveness towards Lara Jean, as she was this porcelain doll you don't want to take out because it would break so easily. The way nobody trusted Lara Jean's ability to know what's best for her really annoyed me from A to B, and I'm not a big fan of Lara Jean, but she showed several times in the book that she was intelligent enough to make her own decisions, but apparently everybody else thought that she was stupid, just because she was sensitive and cried easily. I think the only ones not underestimating her were Peter and Chris. 
 So, yes, I give it 3 stars because I did like very much Peter and LJ's interactions to overrule the annoying things, but it's by far one of the worse 3-star books I have in my list.