I always had a house full of teenager's, my place was the most fun to hang out. I always fired up the grill and feed them. They knew they would have a blast as long as they followed simple rules. If Dad was home the boys could go in the living room and kitchen. If Dad wasn't home the boys stayed outside.
Just be an active part of her life and get to know her friends as much as possible.
Also great advice.
Mr. Bill
Old guys just know stuff!
and,
Old guys just have old stuff!