I agree that it's best not to "mess with Mother Nature."
I too took the pill in my 20s, but had to stop for health reasons. I used a diaphragm for the decade of my 30s and then -- at 39 as I recall -- I, too, opted for a tubal ligation.
Best decision I ever made, since by then my docs had told me it wasn't medically wise for me to have any more children.
You know, this topic sounds a bit startling to us, but, like you, I messed with Mother Nature just the same way. We could make an argument that anything other than no birth control at all is messing with Mother Nature, and almost no one in modern countries does that. We don't want 15 children!
Women use hormones and devices to keep from getting pregnant and take hormones and treatments to lessen the effects of menopause. An enormous number of us choose to help things at various stages of our lives. I'm going to withhold judgment until there are some studies that tell us whether this is harmful or neutral.