How can i become a girl?

ok im 21 years old im 22 in july of this year and ever since i can remember ive always wanted to be a girl ive woren dresses, skirts makeup you name it i mean i stopped for a month cas i was too scared to get told i cant fofill my dream to be a girl i now own some panties girl jeans and thats about it cas i have judgemental parents and my mom clams to be a christain and yet she judges me for the lilest things like finger nailpolish its not illegal lol but what im trying to say is that i want to be myself but i cant cas she will say that god doesnt like it i just feel that my mom wants to control me and theirs no excape what do i do? ps im straight and i just want whats best for me