Wish, I was lucky to move to an area with family, so my first babysitter for my kids was my cousin who is now 13. I don't live near my MIL, who would love to babysit, and my own mother doesn't like to babysit and neither do my siblings who live near me so I don't ask them except in an emergency.
Other than my cousin, I have 3 neighbor girls who are in my church ward who babysit my kids. They are 11 and 12 years old and I have found they are the perfect age because they are too young for boys, young enough to like playing with my kids, and old enough to know what they are doing. Also, since their parents live right by me, if anything did happen, their moms are there to help them. I usually let my kids choose which of the babysitters they want on any given day, too. It makes my leaving that much easier for them, I think. I have found that my son especially (who is 6) likes me to leave. Then when I come home, they are glad to see me, I am glad to see them, and we all like each other again!