I think the style plus the colouring is really nicely done, and by adding the title, it really tels a story on it's own, and I like how you drew Alex' face a little bit resentfull, as if he feels bad for leaving imill behind ;w;
It is interesting i have seen better but still quite good. I my for myself am not a fan of Alex/Mia because they are cousins , but apart from that its still a good picture the color theme is fitting and the emotions from Alex is quite good to see (regret?) .
For the direct characters itself for my taste Mia looks very chubby (like some people would draw Chinese people ) and you have forgotten she normally wears a sweater with a big collar not the collar you have drawn her with (look on the oficiol artworks of her). for Alex he looks to i don't know they look like they are not even from the same town with Mia looking Chinese like and Alex with his longer face more European.
So that's my own opinion to the picture ,please don't look only on my negative critique points and think i want to make your drawing bad , no the point is i just wish to help people to improve.
Anime character look normally very European, because Europe people are an beauty ideal there. Normally in Asian regions you have more rounder faces. If you look at pictures of Asian women and compare them with European women you see the differences.
My family is Chinese, and we live in Sweden. It would be hard not to know the differences.
The beauty ideal I'm going for is not the one we have today but for the one in the Renassiance, which is why I drew her "chubby", as you put it.
Although, I admit I overdid her left cheek there and made her look like she has a round face shape (I meant to draw her with an oval face.) I also drew her nose too low , which is probably why you got an Asian vibe from her.