I'm a 17 year old girl and I find my arms too big! (my legs are skinny compared to em). Are there any exercise I can do to slim them down that won't bulk them up or will I need to go on a diet?

I think a mix of cardio and weight training is a good way to go. I'm trying to get my arms in shape for my wedding in May and I've found that water aerobics is super helpful. In the water aerobics class I take, we do a mix of cardio and weight training using foam weights. I wouldn't worry about bulking up too much. Women don't have enough testosterone to do that. Instead, women tend to just become more toned.

Light to moderate weight training will increase your metabolism if what you are looking for is *fat* loss. You should also do some cardiovascular exercise a few times a week and *change your diet*, do not *go on a diet* or you will not have lasting success.