You're right
I'm actually a bit nervous about what happens when they get smart phones (because all 12 year olds have smart phones now, apparently -- the pressure started this year, and they're only 8).
I read a horrible article in the Guardian at the weekend about a child (=teenager) playing wargames online with his friends, who was groomed and then murdered by the guy who owned the server, despite his parents' frantic attempts to reason with him/ remove access to the computer/ get the police involved.
I suppose like all these things, you can't change the world, you can only do your best to warn your kids.
So from that perspective, maybe it's not such a bad thing that more films are 15s...