Albus only vaguely notes the humming, but being a wizard with very little in the way of Muggle pop culture (aside from what little he gets at Milliways and from Cora), he doesn't connect the song to anything.

He doesn't actually recognize it either.

Room fully cleaned, Albus puts his wand away and sits on the edge of his bed, better for conversing.

"Oh. Um. You don't want to go to university?"