<human>: Can you give me a shortened version of the text?

Ok, so I'm 22 and have never been in real relationship or done that much hooking up. For a while now I've been really wanting a relationship and feeling a bit sad about myself for having been single for so long. 

I'm good with people and have lots of friends, but I was hung up on someone that it didn't work out with for a long time. Since then, my confidence has been pretty low and I've felt really inadequate. I'm also someone who likes to stay pretty free and easy, because I get really stressed out about letting people into my life unless they're just right. I've preferred being alone to trying to force it with someone just for the sake of being in a relationship.

Anyway, I've recently started hooking up with a girl I know. We were sort of friends first, but hadn't known each other for long. We both agreed that this would be strictly casual, and at first I was kind of hoping for more, but  I decided that this was a good intermediate step for me. However, now I'm afraid that she may be starting to get more attached to me and I'm find myself wanting to pull away for no real reason. 

I thought having a casual arrangement like this would be a fun, low-risk confidence booster, but instead it's really making me question myself more. There is absolutely nothing wrong with her; she is smart, funny, kind, attractive, and we can have fun together. Yet, somehow I feel indifferent about the whole thing and I am starting to want more space (even though I'm not even being pressured at all!). I feel like I only want to be involved with someone that I feel I can't live without.

What's wrong with me? Am I just a flaky jerk who's expectation are unrealistically high? Does it make sense to holdout for someone who feels just right? Do I not actually want a relationship? Do I not know what a relationship really means? Any advice would be great.
<bot>: Me (22 M) having casual sex with friend (F 26). Do I or should I want a relationship with her?