I'm a 14-year-old girl. My singing voice can best be described as soft and high.
I don't mind slightly changing lyrics, and working my voice arround a song originally sung by a male.
My performance is supposed to be under 3 minutes long, and most of what I listen to is longer than that (I guess there's always the cutting of instrumental parts and really repetitive lyrics…).
I want to sing something "fun", because I sang a slow song last year.
I can't scream at will, so anything falling into the loud, harsh rock, category is out, and I don't want to sing something that everyone will have already heard.
Other than that, I haven't ruled out any genre completely.
How about Never Again by Kelly Clarkson? I believe it is a really good song for a soft and high kind of voice. Another option is Breakaway, also by Kelly. That might be a good choice because it has some parts that would be great for the way you explained your voice. I hope this helps, and best of luck!