I feel like if this was posted anywhere else a 4.5 would be more fitting but even considering the lack of 18+ I'd regret giving this game anything but a five. The qualms I have are all minor which are outweighed by the generous amount of customization and cute storytelling.
I love the character customization of the MC, the way height and such were referenced as well as colors. It being told as first person also allowed the paper doll MC to not clash against the more handcrafted characters of Tamarack and Qiu; who, both are incredible in the Part 1. I enjoyed how some traits were obvious and others were more subtle without trying to allude to or show the entire hand right away. Qiu for example is always moving around, bouncing on his feet, which not only helps paint a picture narratively but also is a reference to his later ballet interest. Which I liked. Though feels like the story makes a point to let you know at every turn how popular Qiu is, which is cool I guess but I feel like after the first couple times I don't need to be told. But not going to dock points on that since given the story takes place over 12ish years I assume it could just be leading into something more. Plus, the envy/jealous system being there could make it where if you want there to be that extra drama it can be.
Which kind of leads me into the -.5 star I'd normally consider, which is at least in the version I played the tutorial gives me way more information than I'd have wanted on what can/could happen. I feel like the main draw over a story like this is to see how the characters change. But straight up telling me a character before I meet them is going to become gender fluid, or what couples/crushes/pairings exist so far in advance makes me feel like with all the possible paths and roads there are I already have an idea where I'm going. I guess it's to make sure the audience knows what they're signing up for, but personally for me it just kind of dampened the appeal.
Also, at least from what I've seen so far, I feel like the Part 1 character design/story feels a lot better what little I got to witness of Part 2. Part 2 (I believe) is four year time skip which hits you with so much info on what happened that, all the comradery I built with the characters in Part 1 I feel like I immediately lost half of and have to relearn. Who knows though, perhaps parts 2-4 once complete will make those missed developments minor in comparison. Maybe I just missed it in my Part 1 playthrough but with Qiu's development of their identity (Start of Part 2 they no longer use he/him pronouns), I didn't really see much that lead me to believe anything than they were just an eccentric 10 year old boy back then. The designs in part 2 also wasn't so much a fan of; but if you asked me why I don't know how I'd describe it other than they just feel less polished. And no, for me I don't see it as an allegory of that period of our lives being unfinished.
Outside of Tamarack and Qiu there's several other characters as well, which judging from the interactions we have with some of them look like they may fluctuate in prominence in parts 2-4. Liked how our relationship with our mother wasn't forced at all, you can be a brat, an absolute momma's child or almost outright malicious. If you have a personality in mind for your main character, at least in Part 1 I can say you'll likely have no problem acting that out completely; and at least in the playthrough I did it really did feel like the characters reacted to that as well.
I know I may have maybe put too much focus on the minor aspects I didn't like, but I feel like whether you agree or disagree with them you'll like the game so long as you aren't looking for the normal +18 stuff normally on here.