Career help

Ever since I was little I've wanted to be an RN and that's still what I wanted to be up until recently. I'm 18, so I'm still young and have time to figure out what I want to do but I just don't know what it is that I want to do. I really do want to become an RN but I'm just so scared I'll mess it up, or that I'm not smart enough. I've been over thinking everything a lot lately.😳 I've also thought it would be cool to become a physiologist, or a dental assistant.🤔