I began babysitting at age 14 for several kids in my neighborhoods and I charged $9 to $12 depending on the kids. The reason the parents paid it was because they knew I wouldn't be irresponsible and knew what I was doing while they were away. My parents paid my sister and I's babysitters roughly $8.00 and hour (back in the early 1990s) and more when they went out because they wanted quality and the sitter to come back. She was wonderful to us and we loved her. She even asked us to be in her wedding, I was the flowergirl and my sister a junior bridesmaid. We're still in contact today too. She has little girls of her own and she jokes that we should babysit for hers now.
As I got older (16) I charged $10 and hour for one child and $18 for two. Kids are alot of work especially when they're not yours. Eventually I adjusted to the families but if the kids were brats often I would tell the parents why I didn't want to return and be done with it.
Also I became lifeguard certified the year I turned 15 therefore I was certified in CPR Pro, Oxygen Administration, First AId, AED, and Lifeguarding. I paid good money and worked for those certifications and did not feel bad about charging the prices I did. It showed I was highly qualified and I never recieved a complaint.
Highly paid sitters tend to be much more reliable than not. Being able to trust someone else with your kid is a huge thing but it also comes at a price.
Don't freak when a teen asks for a hefty per hour, ask for a list of certs and if you still feel it is unreasonable then negotiate or find someone else.
That price is totally fine if you ask me.