I've found that I'm much more of a "hot commodity" now at age 32 then I ever was when I was younger, simply because I've had time to work on improving myself. If you constantly worry about what girls think of you, that shows and you're compounding it by worrying too much about her finding out about our fetish. You'll find that if you're a real fun guy to be around, she'll be more receptive to whatever it is you like because she will just enjoy spending the time with you. Who knows, she may even get to like it herself if she doesn't already...