Paying the Babysitter

A little back story...

I live in Indiana, I am 17 years old. I have taken child development classes and babysat before (not that that is super important). The child is 6 months old and I babysit him for 6-7 hours at a time.

So my question, how much do you think I should get paid after a watching him for 6 hours?

I babysat one time so far from 4 pm-10pm and got paid $20. I’m not expecting to make a ton of money, but I kind of thought it would be more however I do understand that I am a teenager.