I'm not sure. I mean I started Halo when I was 10 years old, I am now 18 years old. I know that if I had a parent like that and you advised her not to get it me, I'd be heartbroken, considering Halo is one of my all time favourite games. On the other end, you were just doing your job. If you didn't do it properly, then you'd likely be in trouble with the manager if he caught you red-handed selling a kid an M rated game. So for your sake, yes you did the right thing. Not sure about the kid though.