1. They may be playing with your head, they may not be fulfilled in their current relationship, they want to use you as a back up, and finally they just like the attention.
2. Your setting up yourself for failure by basically saying she's better than you because she's out of school. I'm sure she doesn't care about it at all. If you keep "putting her on a pedestal," you're gonna fail no matter what.
3. Nope as long as you are social at the right times. I'm not introverted so I can't really comment.
Have confidence in yourself man. For the girl that's out of school is concerned, to put you at ease, she went through what you are going through and is on;y one year removed for it. No big deal at all.