I'm 18 but felt every bit of this movie to the core. It's so relatable and the ending is so touching; I teared up. It's a really good reflection on how my teenage years had been, and I could really use a lot from this movie's message even when I'm a bit grown up now.
Aside from the messages, the animation, writing and puns are so well articulated that they're smooth as butter. Some of the jokes are kinda genius and a bit self aware, adding to the genuine feel of the movie.
The characters are also very likeable as expected. Eventhough there are 7 emotions (8 if you count Nostalgia), everyone has a chance to shine. Though some of them are abit lackluster, I'll still say, every characters serve a purpose and are not at all out of place.
One of my friends rated this 200/10, and he's hard to impress! Take that info, as you will.