Girl Problems? Help please.?

I need some help with girls, I know this question probably isn't going to instantly solve my problem, but here it goes. This may be long.

I just graduated from high-school, I had a girlfriend but we had to go our separate ways because of school, since then and I've turned 19.

But the problem is that, i'm attracted to a small number/specific type of girl, and most of the time those girls already have boyfriends, or they don't want a boyfriend at the moment. Thats how I feel sometimes, like I don't want or have the time to give my attention to someone else. Because, to be honest I do like some alone time, but then there are times where I wish I had a beautiful lady who loves me for who I am, etc.

Another thing, is that i'm afraid of rejection, so most of the time I don't try to put myself in that type of situation, but then later regret it.

There are times when I see a girl in a store or something and just get star-struck by her, but I think about how cheesy she might thing I am for hitting on her in a store, without knowing her at all. I'm the type of guy who gets the know the girl and THEN asks her out, not waiting for the friend-zone of course.

Some of you may say I might be bi, or gay, but no, trust me i'm not.

I'm confused about if i'm even going to find my significant other because of me liking certain types of girls(i'm sorry, I can't force myself to like a girl just because she's a...girl) and me basically being a afraid of rejection.

I get told very often about my looks, and how mature I am and whatnot, so if thats true then why don't girls ask ME out. Could they be.. intimidated or am I too mature for a girl my age? I just really need to figure this out. Also, i've never been the type of guy to go out-of-my-way for something unless I REALLY wanted it, which could be another reason.

So, guys do I take the chance? Do I just 'wait' for 'her'? It's really been bothering me lately...

Thanks.