I'm 16, yet I look 13!?

I try to act mature (not loud and obnoxious, always polite and friendly) I wear some makeup to accentuate my features, I wear mature and stylish clothing (mostly vintage or stuff from H&M none of that hollister or Ae crap). I have really long curly hair and bangs but I think people mistake me for 13 because i'm pretty short compared to people my age (5'2) and I have a really tiny bony structure, and since i'm small chested (32a) and have an innocent face with really round cheeks and big brown eyes I look naive. How can i appear older? At the most I look 14 or 15 but it still annoys me because people treat me differently if they don't know me they assume i'm really young.