But some turtles have very long lives. You didn't say which turtle you have, so I can't say how long it is likely to live.
When someone says that a cat has nine lives, they mean that many dangerous things can happen to a cat and the cat often seems to survive them. Turtles are really quite fragile. In many places, they are an exotic pet, meaning that they can't live in the natural environment of the place where they are kept.