History of Premature Births

Super excited to be pregnant with number 3! I'm due January 29th and we are so thrilled! Yet very very nervous. I have an 11 year old, and a 9 year old. they both were born very premature, my first at 33 weeks, and my second 28 weeks. I was only 15 years old, and 17 years old at the time. It definitely is a different situation this time around. (Better relationship, no "shame" feeling, I'm not worried about what people think this time around) My doctor has reassured me that she is going to do everything possible to make sure I make it to term but I cant help but think the worse. Any of you ladies had premature babies? Did you carry to term after?