You really don't have the hormones to bulk up. It's HARD to build significant muscle unless you are genetically gifted or taking banned substances
If you keep your weights where you can do sets of 12-15 repetitions of an exercise before muscle or form failure, you'll end up with nice tight muscles without much bulk. Generally on women, "bulk" is fat on top of muscle. Make sure that you workout your entire body, not just your legs or waist, or wherever you think your "problem areas" are. If you are new to weight training, try to get a trainer to give you an orientation session so that you know the proper form, and what exercises to do for each body part.
Good luck! We have a Ladies Who Lift Forum here is you'd like to join us or ask questions
Mel