Daniella, I don't know how old you are now, but suspect that havinf babysat at age ten may have played some part in the fact that you did not have unwanted babies.
I too started babysitting young - age 12. And believe me I was very careful about NOT getting pregnant before I was SURE I was ready for the responsibility.
Babies themselves can be the best form of birth control. With my granddaughter in the house, it wouldn't surprise me if her aunt (my dd) never has kids.