I've never had any sexual encounters. At 16, I had a romance that remained platonic only because I was too scared to respond to the girl's sexual advances. I, in effect, friendzoned myself.

Now, I'm a 19 year-old virgin with no experience whatsoever. I have a muscular aesthetic build, and a good sense of style; I've also read books on seduction and body language, so I can tell many girls are into me. But I just don't do anything about it.

A recent example of my dilemma: A week ago, a cute girl came up to me in the club at college/uni, taking my hand and asking me to help her out the crowd. She then tells me shyly how she "thinks I'm hot". Then I turn her down, jokingly, saying she's old young for me (2/3 years older).

Situations like this have been happening to me for ages. I always falter when it matters most, and prevent pretty girls from entering my life. I think I'm sexually repressed. What can I do?