stretch marks during pregnancy

During my first pregnancy there was one month when I put on about 10 pounds and I got stretch marks galore on my belly. I've gained and lost weight but these are the only stretch marks I have ever gotten.

During my 30s I noticed that other girls my age were aging faster in the face. My skin was still tight and I didn't have lines or wrinkles.

I wondered if what caused my early stretch marks also kept me looking younger than my peers. In other words was the makeup of my skin just less stretchy, so it did not losen up until decades after others my age?