hmm...well J Lo is not "thin" by any means and from what you described of having a muscular lower half and more petite upper, I would say you are already there. She has a very curvy figure that at 97lbs will be hard to emmulate. What aspects of J.Lo's physique do you find appealing ?

From all that I have read, you just need to drink more water...at least 100oz a day, get your diet ratios in order, you can look at my NHE journal at my daily diet and I would be glad to help you with meals. Join the gym or start start working out at home with free weights or videos. Since you are so tiny and have a small amount of weight for your goal the exercise really is going to be key in getting you where you want to be.