My mother's first child was born at 28. and her last at 41. However, she too didn't mess with her system.
She squeezed them in close together.
Apparently, the Pill back in the late 60s was still pretty new science. She was also taking antibiotics at the time and they did something to counteract the hormones.
I was on the pill for only a short while, I never liked how it made me feel -- it was very a very strange, unnatural time. Thankfully, my body bounced back quickly--because I've heard horror stories of women who NEVER get back to normal. We'll be trying (possibly, still haven't decided) on baby number two next year. If we get pregnant, great, if not--there's always adoption.