It sounds like your girl is a keeper. If you're saying you have chemistry, and you could see her being your wife, than make it so.
You seem like a level headed dude. You don't seem like some one that wants to just sleep around. Since you said that you your not into easy woman and the party scene. I'm very much the same way. I missed out on what could have been good when I was a little younger than you because I thought the same thing.
I then met some one, who with in 6 months thought the same thing, she wanted to test the waters.
But because I didn't hit the bars night in and night out, all my friends were with people that they ended up marring, it took about 6 years before I finally met some one I could settle down with.
While yeah, you have the moments of, "I wonder", building a life is a whole different adventure. I know right now this sounds scary, but having a kid makes it worth settling down. On most day's anyways. LOL!
I ran into that girl about a year ago. I was with my daughter. She was with hers. But in her case she was divorced because she got knocked up why testing the waters and the guy ended up being a deadbeat. She also said her breaking up with me was a huge regret, but she was happy I found some one I could lean on.
I would say, if you're not already, move in together, live your live like a married couple. Get into fights about money, whos cooking tonight, who turn it is to clean the bathroom,ect, and can come out still loving this girl, then it where you should be. Noting says you have to marry her right out of school, enjoy a year together, go on vacation. Look back and see if you would want to do it over and over again, and with kids. Then consider marriage if it's a yes.
Just because you might have an itch, and your friends say you should do some thing about it, it might cause more issue in the long run. Not an easy decision, but I'm glad not to be in that position any more, and next summer celebrating my 10th anniversary.