Im really nervous to do stuff .. how do i push my self to do it?

im tired of being prude and i actually want to do stuff with guys . im not saying i want to be a whore but the guy i have had a thing with for 4 months and i havnt done anything because im even to scared to kiss him . i always feel like im going to be bad at doing stuff. how do i push my self to acutally do it? because i know im ready its just whenever i have the chance i pussy out