[CoMaToSe]

Okay, once you all get over your inevitable "bullshit" responses, you may be able to give me some sound female advice. On to the story:
Okay, there's this girl I've liked for some time. We have fun hanging out, and we flirt around a bit. I really like her.
Anyway, this past Thursday I went to a party, the sort where nobody leaves single. Not even the fat kid (IE Me). She didn't go because of parental restraints. I was sad. I drank and had fun. Then near the end of the party, this girl comes up to me, we start dancing, and eventually we excuse ourselves for a few minutes. I won't go into details, but let's just say it got a bit more serious than a typical party hookup.

Anyway, flash forward to the next morning. No, I didn't sleep with her or at the party, I went home like a good boy. Anyway, I realized I'm not really interested in this second girl, and I still want to go for girl A. To exacerbate the issue, I recently learned that a friend of mine is also interested in her.

So here's my question: Would it be stupid and selfish of me to say fuck the second girl and continue going for Girl A, considering that things got pretty serious with this second girl, I am safe and guaranteed a relationship with her, and that my friend wants to go for girl A?