I have to babysit 13 year old boy, I'm 14???!!!!!!?

I'm 14 and I babysit these kids that are 9 and 4. I went over yesterday for the first time and I was told that the older kid was anti-social and probably would spend all the tim eat his friends houses or in his room, but he didnt, e came home and I had to watch him and he was more exhausting then the younger ones because I know him from school and when his younger siblings misbehaved I could reprimend them, but it's hard to watch a kid thats taler than you.