I feel I've been single for too long?

I'm 22 years of age and rather embarrassed to say that I've never been in a relationship with a girl. There are girls I fancy but feel I cannot be any more than friends most likely because they are in good relationships of their own, or they might not feel the same way about me. I'm not like most people my age. I'm not into modern pop dance or electronic music. I like a lot of rock music of all ages. I don't like clubbing since I feel I don't belong. I get teased at work because I've always been single and I have a bit of a crush on one of my work colleagues. I've always like her and we always get on well. Just lately though I've discovered that she likes one of my all time favourite bands and we actually have so much in common. The problem though is that She is already with someone and I wouldn't want to destroy our friendship by telling her. I feel slightly jealous when I see other young couples holding hands and kissing. Sometimes I think I'm better off holding on for the right one but my worry is when it's going to happen. I'm worried I'll wind up fraile and old before I meet anyone. When I do go out I'm so quiet and shy I don't have the bottle to go up to someone and say hi. Which doesn't even help matters. I'm also not great looking. I'm trying to do something about it. I'm 5ft 10 and weigh just over 14st. There isnt a bad bone in me and i know i can treat them right. Is there any advice you can give me to help me find that someone special. Sorry for the wall of text I used my phone to type this and it took ages! Many thanks I will give 10 points to the most intelligent and useful answer.