For a 13 year old, I'd make one of the "modern quilts". I just finished a fat quarter lap, square within a square that I cut and pieced in just an afternoon and I'm no quilting speed-demon. Being a young lady, I'd keep it kind of trendy. Turquoise with red or very bright pink. I made the aforementioned lap in bright turquoise and bright lime green. Also have seen turquoise paired with a great shade of orange. Not your traditional colors, but younger folks just love them.