I feel exactly like you. Did you spend your formative years at school avoiding anything that might make you look different - i dont mean different from your peers but different from yesterday.
I used to be too self conscious or scared to even wear my hair in a different way in case people noticed and maybe thought badly of me. It was crippling and the worst things is people DID pick up on what I wore or changed. One nasty bully in particular sniffed out my anxieties and vulnerabilities. If I made any attempt to adorn or decorate myself she soon made me feel shit for trying. I mean things like hair slides or shoes.
I, like you, am mostly too afraid to wear make up. I have no skill and am too afraid to experiment. But I do know you can wear what you like. Plenty of people I've seen wear mascara and lippy and nothing else because they don't like foundation and concealer, don't care for eyeshadow but just want darker lashes and a bit of colour on the lips.
I have put on make up at home, alone, just for the joy of trying it. I've also worn make up to parties and overcome the self consciousness by remembering people like me, me the human being inside, and are looking beyond my face anyway.
Generally It's tinted moisturiser, eyeliner, mascara, blusher, lipstick. Eyeshadow if at a party and I can be sure the lights are dimmer 
My sister is the person who assured me that make should be fun, something to play around with.