How can I look my age?

I'm 21 but I have a body of a 14 year old and I also cut my hair a year ago so now it's up to my ears so I seriously only look 16. I don't wear makeup and I don't wear weaves or wigs, totally against them. And I'm not about to start wearing them just to look older because I shouldn't have to! My wardrobe is age appropriate but I don't fill out anything because my body is premature. I have these f'n double D boobs and that's it. I like being naturally beautiful but it sucks when you're at work and one of your co workers ask you if you've started looking at colleges yet because they think you're a senior in high school when you're really a senior in COLLEGE 🙄 Does anyone have any tips to suggest?