Question for skinny girls. How to get curves?

I'm a 23 year old female, who at 5'4" weighs only 107lbs. Most of it is genetics, but I haven't always been this skinny. At one point I was pushing 130...this was when I ate french fries everyday and nothing but junk food. It's sad to say I looked the best at 130 than I ever had in my life. A few years ago I got really health conscious and exercise 4x a week and eat healthy foods. I eat a lot, but because it's healthy I just don't gain a pound! I'm so sick of looking like I'm 16 years old because of my weight and everyone thinks I'm maintaining this weight because I think it looks good.. wrong! I want to be at least 120pounds. It's just so hard unless I go back to my old ways of not exercising and eating junk food. It's so discouraging because I make the effort every day to make healthy choices and exercise, but instead of getting good results I'm just a twig. ugg. I'm really confused.