It sounds like infatuation, the wonderful beginning stage of falling in love. If you think you want to persue this relationship further, make sure you find out lots and lots and lots of things about each other. What does she think about children, cats, comic book stores, heavy metal music, wearing perfume, you wearing cologne, going grocery shopping, going to the doctor, spending time with her family, gardening, keeping a clean house, cooking etc. Find out anything and everything about her. You can even play the Q & A game with her (which is where you both write down 100 questions, some intimate, some regular and ask and answer). The infatuation stage doesn’t last forever like @gailcalled said, but it’s a really fun way to get to the next stage.
The next stage is where you are really going to figure out whether you are in love. This will be a time in which you will find out whether you can leave your girlfriend on her own and not be overcome with jealousy that she will cheat on you. You will decide whether or not you can imagine yourself living with someone who doesn’t always look like a million bucks (this is all people by the way), like when they have an acne breakout, or they didn’t have time to wash their hair, or you see a little bit of cellulite on her thigh, or she hasn’t yet put on her makeup, or she gets a slightly too short hair cut, or she wears a dress outside that you think is a little too low cut. What will you think about all of these situations? This will be the time when you figure out if these small, but ordinary things are OK with you. The first time one of you gets sick with a bad cold or the flu is a telling time as to whether you will be able to be together for the long haul. People are often at their worst when they are sick, are you up to the task of taking care of her when she looks ugly, needs help to the bathroom or throws up on you and asks you to get her things and tells you how much pain she’s in? And is she willing to do the same for you when you are sick? People that are really in love with not only put up with these things, they’ll do it gladly.
During this stage, you will also have to evaluate your deal breakers. Does she trust you to go off with your friends, without her and not get jealous? Does she have a warm and loving family that accept you into their lives? Does she have nice friends? Does she smoke or take drugs (are those things problematic)? Do you both have a strong ability to communicate honestly and effectively without hurting each other’s feelings? Are your lovemaking patterns and desires similar? Do you share household responsibilites? Are your sense of cleanliness and order similar (slobs and neatniks rarely last together for example)? Are you both in agreement whether to have children or not, and when to have them? Do you both have a similar sense of humor? Do you have a similar belief or lack of belief in God? How and where will you spend the holidays? Do you agree upon how to save and spend money? These are the hard questions that they often ask you in pre-marital counseling. Often, couples who think they are in love, have never even talked about any of these super important potentially deal breaking subjects.
So enjoy the ride for now, but make sure that you start really getting to know each other in all ways. One day you’ll wake up and know for certain whether you were just having some lustful fun, or whether it’s real love. You will know and you won’t even have to ask the question. Good luck to you both : )