My antenna is about 40' up, but it's a fan dipole in a maypole configuration. So 3 sets of dipole legs going off in different directions. The dipoles act as guy wires holding the mast stable. My dipoles are 160 80 and 40. But obviously the lower bands are not high enough for a 1/4 much less 1/2 a wavelength. So pretty omnidirectional, even NVIS.
But the higher bands work better for me, at least for DX-ing.
My son doesn't have an HF rig yet (those things aren't cheap!), but I involve him in all my ham radio stuff.
He had a good Freshman year of homeschool. His ham radio studies (videos, labs, practice, studying, etc.) constituted a 1-year science credit, based on the # of hours he put in. Since he aced the tests, he's getting an A in the course.