How do I tone my arms and stomach?

I'm a 13 year old girl and I think I need to tone my body a little. My arms are kinda fatty and my stomach is a little squishy and when I bend over I have fat rolls.. HOW DO I GET RID OF THAT?? I don't wanna ask my parents how to do it. I'm just looking for secretive little ways to get rid of excess fat and muscle up a little. I don't wana look super muscular, just a little more fit and bikini ready. Help?