second semester lesbian

A girl (who is usually studying Gender Studies) who aggressive adopts a lesbian identity late in the first year of University/College study. However by the time graduation rolls around (unlike an actual lesbian) they have abandoned this identity and are often engaged to a soon to be doctor, lawyer or accountant.

The term was used at least as far back as the early 2000s by the sex and relationships advice columnist Dan Savage.

"I'm going to come out to my folks at Christmas time."
"Maybe wait till you've had at least one serious girlfriend or even hooked up with another girl,? Make sure you aren't just a Second Semester Lesbian?"