Actually if you want to go for the girlfriend thing then you
might want to act like you just want to be friends with her, nothing more.
It's funny to see how the friendship frame works with them,
because this gets them thinking, often for the first time "Wow, maybe
I just found a man that is smarter than me, knows my little games,
and HE has higher standards than ME for once... and now he's talking
about being 'just friends!' Oh no! Doesn't he like me? Doesn't he want
me like all the other guys?" A key here is to always keep them
guessing... never get too into them or they'll get right into their old
games, etc.
But then again you could end up being nothing more than a friend, heh it's up to you
On a side note, you're 15 stop dicking around online and start doing stuff.