You will find in some parks she will, but we have to go with whatever each park deems as children. It's crazy as I think it should be when a person actually becomes an adult but as you know, even with airlines etc. they seem to make their own mind up.
So you'll need to check at each park. I know that the Ingenia group that just joined us with 32 parks in QLD and VIC they consider children as under 17, so here you would, but not all do.