The best attitude when beginning a relationship is to not obsess over it. Being in love is very exciting, but if you let it become the sole source of happiness in your life, it could also be your biggest downfall if the relationship fails later. Keep up with other hobbies/activities that entertain you, and try to keep yourself busy when you're away from her.
If you come to the realization that the girl was indeed manipulating you, or simply wasn't interested, don't let it get you down. Keep in mind that despite how you currently feel, there will likely be another girl you find attractive soon enough, and perhaps better suited for you. The world is filled with girls, and the chances that you'll love only one is unlikely, unless you refuse to let her go (which you should if she was manipulating you).Remember this, just because the girl your dating DOES act this way, doesn't mean she's manipulative. She could just have an outrageous/overly-confident personality. Though i would suggest keeping your guard up.