I really want to babysit I know how to do everything but nobody thinks I'm responsible enough to handle it , but I know I am able to I do it all the time ( with baby dolls) do you have any advice to allow people to trust me

p.s I'm 11 if that has anything to do with it

Yes, you are too young. I would never leave my small children alone with someone your age for very long. Your best bet is to get work as a mother's helper while the mom is at home but busy with other stuff and you would entertain the children for her.

but I know I am able to I do it all the time ( with baby dolls)

Baby dolls don't cry, don't need to be fed, don't need to be changed. When you're done playing you put them on a shelf and forget about them until you want to play again. Real babies are very different.

The fact that you think playing with dolls has given you the skills to babysit living children shows that you're not ready to babysit.