15 year old girl,think I'm getting taller?

Right now I'm 5'7,same height as my mom.. But we noticed I seem to be growing a little. Maybe a centimeter or 2. It could just be us seeing it, since I've been hoping to grow, but I really didn't think I would. I wanted to know is it common for girls to have a growth spurt at 15? My sister seems to think I will probably have one since when she was between 15 and 16 she went from 5'9 to 5'11 but we have different dads (same mom) so I probably won't be as tall as her. But,I could go to 5'9 or something,I guess. IF I have a growth spurt. What do you think? ^^ Opinions? :D