I don't know what to do

im 17 born a female but don't fell like I am a female I never knew what transgender was until about a year ago, but ever since I could walk and talk I have been leaning more towards the male side of cloths toys pretty much everything, BUT now I know what transgender is I know that's what I am.

I'm need help letting people see that, I have been telling people that's what I am but they just think it's all a big joke, does anyone know what I can do to make people see me for who I am and not for who my body tells people I am