I'm not going to sugar coat this or put too much effort into this review, I'm just going to leave it at this. This is a story anyone, young or old, weeb or not, can enjoy. The show has very few flaws, and the few it does you'll feel like an asshole for pointing them out.
I've talked to various friends, some who aren't even into anime that said they have enjoyed this show. Again, this is a show that anyone can enjoy.
Basically I can't think of any flaws I can name here, and I find no need to spoil any of the story, so I'll keep it short.
10/10 around the board. A truly fitting MAL number 1.
11/10 story
10/10 Art
10/10 Sound
11/10 Characters
10/10 Enjoyment
10/10 Overall.