Getting Fit in Your 20s

a question for the exercise gurus:

I have always had a fairly muscular body and growing up I was always playing some sort of sport.  I am petite and fit now, but I am extremely uncomfortable about my large thighs.  They are disproportionately large for my body and I don't want them to get bigger as I have been exercising more lately.

What exercises build thigh muscle the most?  Lunges, squats?  How can I work out (aerobics, weights, running, other ideas) without my legs getting bigger?

This problem is really isolated to my thighs.  My butt and calves aren't really an issue at all.

Thanks for the help!

Hi! Lunges and Squats are what would help build, sculpt and define your thighs (basically all legs and butt) more than anything else. Unfortunately many women have the same problem and the trainers at my gym encourage us to sculpt and define other parts of the body (like shoulders and arms) to take the focus off our lower parts. They claim having better defined shoulders and arms will help give the illusion of slimmer hips,butt, and thighs.