Just talking to a woman doesn't automatically make you seem like a creep. It's all in how you do it. If you go over all nervous and it refects in your body language or voice, you'll come off insecure, weak, and looking like you're not comfortable with yourself. If you go over with an overbearing personality you'll just look like an ass who's annoying. What you should have done (and try this next time) is glance over at her to see if there's something about her you could comment on to use as an opener to start the conversation. Always, Always stay away from commenting on her physical attributes of any kind. If she's even halfway attractive she knows it because guys let her know all the time. It's boring to her. Instead, pick something like her shoes or fashion or things that would interest most women but they never really meet guys who notice or talk to them about it. After you decide what to comment on go up and do it. See how she responds and just get a normal conversation going where you can riff off of what she's saying like if you were talking to a good friend. Do that for a minute then tell her you gotta get back to your seat and get her number. If you do it right and have the confidence she'll most likely respond favorably and you'll get her number.