She didn't have her first child until she was 25, so that math is more generous than the reality, at least as it relates to her decedents. Her daughter has 4 kids with 3 different guys, and made it well-known (she said it herself) that she was trapping army guys cause she was "increasing her income" by having their children and "you're never lonely on-base" (making it known she slept with all the guys, married or no).
The granddaughter never passed 8th grade, proudly admitted to prostituting herself at 13 ("they pay extra for young ass"), and gave birth at 14. And trust me when I say she actively chose this life -- she was straight out of a Jerry Springer show, bragging to everyone how she had a "lifestyle" to keep up and we (the horrified family trying to get her help) were all jealous.
Honestly, theres so much backstory here, but you'll just have to trust me when I say the teenage pregnancy part is only a symptom of their trashiness, not the cause. They're horrible people.