I am due sep 20th and I am carring twins. I've gained a little more than 68 lbs and I don't have strech marks. When I deliver will I have strech marks? Like because my tummy isn't hard from the girls? Will it like sag or will I just be lucky and not have them?

You may or may not have stretch marks. All depends on your hydration and your particular skin type.

In the beginning, right after birth, you may not notice a big difference in the size of your tummy, other than it feeling like jello. But slowly it will go back to your original shape with proper diet and exercise.

I didn't get strech marks with my first baby, but since I am 4 times the size I was when I had my first I didn't know

I didn't get the majority of my stretch marks until after I had my son. I had a ton of water weight and a few days after I had him I lost weight so fast it was ridiculous. I had very few while I was pregnant, it was after I had my baby they popped up.