I think that's a GREAT idea. I'm 13 as well and i know I'd love to get burnt CD's for my birthday! Everyone has different tastes in music, but here's a bunch of my favorite bands...
THREE DAYS GRACE,
the frey, A Chnge Of Pace, Staind, The Cars, Southcott(We'll Take This Outside) Fergie, BOYS LIKE GIRLS!, Cascada, nickelback, Augustana, CREED, Martina McBride, SUGARLAND, Joe Nichols, Albert Hammond Jr , Evanescence, rascal flatts, all american rejects, Red Jumpsuit Apparatus, faithe hill, Akon, mariah carey, mims, Heartland, josh grobin, AC/DC, Hinder, aerosmith, billy joel, Alana Grace, carrie underwood, Heartland, Thousand Foot Krutch , goo goo dolls, Eminem, R Kelly, Natasha Bedingfield, Keith Urban, Mandy Moore...
If you lookin spacificly for some songs, heres a few of my favorites as well...
Geeks got the girl - American Hi-Fi
Promise - Simple Plan
When Your Gone - Avril Lavigne
Animal I Have Become - Three Days Grace
Good Life Feat - TPain
Zero - Hawk Nelson
Over It - Katherine McPhee
Thunder - Boys Like Girls
The Great Escape - Boys Like Girls
Crazy - Simple Plan
I'm Just A Kid - Simple Plan
Hope I was able to help. Good luck with her peasant!