<p>I'm around your size, 5'2 120lbs. but i used to weigh around 105 before screwing up my joints which eliminated a lot of exercise options. but anyway, i was pretty thin, but pretty muscular, but not buff, which in my opinion is better than just being thin. I was very happy with my body then. the way i got that way was playing soccer, which involved a lot of training and exercise. I did long distance running (1-3 miles depending on the day), sprint drills, circuit training (series of excercises that you do one after the other, so you tone while also getting cardio and burn some calories). i actually enjoyed circuit training a lot. My exercises mainly focused on core and lower body muscles, and my upper body exercises were focused around the back, chest and shoulders to help with throw-ins for soccer. so everything was pretty well toned, and then my arms were kinda puny. but playing the cello actually helped that, but a different way to go would be to just use 5 or 10 pound dumbells in a variety of exercises. if you want ideas for circuit training, i can tell you what i did, just ask because i don't want to list it out if i don't need to. then on top of that, there were practices and games 3-4 times a week (all things mentioned above were done once a week, but running was every day that i didn't have a practice or game). so the soccer itself adds in a lot of running. one warning, when i was that size, people accused me of being anorexic, and i did look a bit too thin in some old pictures, so maybe set your goal to maybe 108-110. but that's just my opinion.</p>