Where did I go Wrong?

Ok, so I thought it would be cool to write a story about my alter-ego. The idea came to me when I was playing tennis this morning.
Random, I know.

Kay, so basically the main character/narrator, the story is in First Person, duhh; is a very bad girl. Naughty, Naughty. Tsk.
And that's COMPLETELY the opposite of me. I'm well-behaved and stuff, you can see my halo, no lies. =D
So, having a bad girl as my main character sounds awesome, and I plan to have a guy come into her life and change her completely, kinda like "A Walk to Remember" minus the death, because that's just too sad.

I don't have any plot plans yet, I'm just gonna come up with things as I go, so enjoy!