<human>: Could you distill the essence of the text into 1-3 sentences?

Before you answer this question please read this description because it's not as straight forward as it seems. I know a lot of people my age have gotten engaged and/or married at my age but I'm still wondering if I should be in such a serious relationship when I have so much more of my life left. 

Before I get into the the details of the issue I'll give you all some background.  My girlfriend and I have been dating for over a year and everything is going great, at least between us. We have so much in common and she's become one my best friends. I enjoy the time I spend with her and I love her (I don't know exactly what it means but I feel it if that makes sense). Also this is my first serious relationship. 

We've talked about a future together (moving in together, etc.) and part of me is excited about all of it. But there's another part of me who is scared about it. And I don't mean in the "what if it all goes wrong" way because that idea doesn't really bother me. If we break up it would suck but I would move on eventually. What scares me is the fact that I'm only twenty years old and it seems like a big part of my life is already being decided. 

I'm the kind of person who needs a lot of time alone. I enjoy the time I spend with others but at the same time I need some balance. If I spend too much time with other people I start to get really uneasy. Which was already a bit of a problem when being in a serious relationship with another person. As much as I love spending time with her, I need time away from her as well. It's got nothing to do with her and I've told her that but I know it upsets her. The reason this matters is because if I were to move in with her or anything like that, I would lose almost all of that time to myself.

Also, I want to be able to go off on my own and build a life for myself. I mean sure I want to commit my life to another person some day but I don't want to do that right now.
<bot>: I'm worried about committing my life to another person and losing a large chunk of my independence at such a young age.