How old is your daughter? Are you the parent? If so, and you feel this is not appropriate viewing for her - say "no" and mean it. End of discussion.

geez....

Convince her...of what? That you don't want her to play that particular game because it has nudity? Because it's restricted to age 17 and up? (Who decides that restriction? A bunch of Puritans?)

Remember, when we tell our kids no, that only encourages them to do it, unless you take the time to explain the 'why' behind your decision and allow them to understand.

Parents should be parents and not best buddies, but that doesn't mean alienate your kids. Parents should teach their children. You can ban her from playing it, but that doesn't mean she won't play it at her friend's house.

Better to allow our children to see nudity than for them to see violence.

maybe as her parent, you can try to convince her to play other games also, try to explain that playing godfather 2 is not allowed for her because she's too young. Try to divert her attention in other stuff maybe playing sports.

There are tons of games, that your daughter can play online or download them and play offline.

Check out some excellent games from Alawar.