Annoying Game Center app

I’ve read everything about Game Center, trying to find a way to exorcise it from my iPad and iPhone. I don’t use it, don’t want it and am sick and tired of having it pop up every time I open a game. I turned it off, it doesn’t care. Every chance I get, I say NO…. But to no avail. I know it comes pre loaded with Apple devices. So do many things that I don’t use. But Game Center is the only one I am unable to shuffle off out of sight and out of mind. If it would just not pop up and beg to play with me! I’m OLD, I don’t play with anyone but my grandchildren! And I don’t play computer games with them!