How to look like a woman and not a girl

Idk why I’m so insecure and sad lately about my appearance but!! I’m 19 and turn 20 in about two months and I still look like a child and it makes me embarrassed and sad because some girls are out here loooking amazing. I’m really short and have no ass or boobs. I don’t dress childish and I wear minimal makeup everyday. Any tips lol besides plastic surgery because I can’t afford that