@dropdead,
Whoa there, cowgirl.
Here's the deal. Spend some time together in a relationship or at least for some dating. Do the kissing and whatnot then. Don't do it all in one shot. Otherwise, you're setting yourself up for precisely this type of performance anxiety.
So - go out on a date. Or two. Take in dinner and a movie or play mini golf or whatever. Your first kiss should have some anticipation and mystique behind it - not an anxiety about whether you smell (you most likely do not).
Basically, don't have first kisses, BJs, sex, etc. as if someone was chasing you to just get it over with. Whether you wrap any of it up with emotion or not, you'll be a far happier person if you don't rush it like taking off a bandaid.