Never understood why anyone asks out girls...its so chode...
Think of it this way...
A guy who has options wouldn't be asking a chick out? Why? because he has an abundance of women, he isn't too worried about getting this one girl. Meanwhile the other guy he is asking a chick out and he doesn't even know the chick. I guess he mustn't have any other options because he is so quick to go right into a relationship.
Point I'm trying to put across you look like a AFC who jumped out the shadows saying "I have a crush on you". It may work here and there but the overall frame that your in is a rather boring dating frame of bf/gf there isn't no sexual tension or any of that good excitement. Sex isn't her way of getting validation or your acceptance anymore, now its basically you working to get sex while she logically screens you.
Overall if you actually want a chick, then game her the right way, don't be an AFC.