How to lock settings on iphone 4s?

Is there a way to put a lock on settings with a passcode. I have a 4 year a old sister who uses my iphone to play games, but she somehow went to settings and turned off my icloud, that deleted all my pictures saved on the iCloud. I don't know if it was her, I just saw my icloud switched off and all my contacts and photos were gone. When I turned it back on my contacts came back but my photos didn't.

Lock case

Go into restrictions and set it up as you like.