Why can’t I do anything???

Okay so I’m 17 and I’m a horny teen I have had many opportunity to have sex, and I want to but I can’t and idky like onetime my boyfriend was fingering me and it felt good nd shit. I wanted to touch is dick and do shit but my mind ig kept stopping me ig I just get super nervous which that Normal but other people can still go through with it and I can’t. I don’t get it like I want to do stuff but I can’t someone please help me what do I do??