Tiny, Curvy & Ready to Tone! :D

Hello! All of my friends call me Fushi. I'm a 23 year old off and on again college student from the Sunshine State. I've been tiny all my life but due to my curvy figure I find it easy to look bad with a few extra pounds. My measurements from several months ago are 34-25-40 and I'm 5'2". I've gained a few pounds since then (135->142) and got a sedentary desk job. I can feel my body changing because of it. I want to stop this gaining process before it really becomes an issue. I started weightlifting three times a week at a nearby gym with my guy friends. I also started watching what I eat and trying to watch where my calories come from. My overall goals are to have a very toned tummy and firm butt by the time summer rolls around. I've never worm a bikini in public because I can be quite shy about my round bottom but this year I want to wear one loud and proud. Any other wide-hipped little ladies out there? Any advice for a new weightlifter?