Gloria´s first time ended with GDS awakening incident.
Roommates were couple, and she always fled when she felt their passion.
Of course, I can't be 100% sure, but I'd bet she had more important things to do than sex.
For example, to survive.
Her first time
started with her GDS awakening incident, so things didn't reach to the moment of truth. And considering her akwardness when she tells Katie how she can feel the passion too, I'm guessing she learned when to flee... but maybe after some initial experimentation. That's just my take on it, obviously, I could be totally wrong.
Also, been on the hide and fighting for survival doesn't exclude some release every now and then. She's been working on a cafe after being kicked out of home so she was having a relatively normal life even after the inicident which was about 2 years ago. It seems the hunt for her only got serious very recently.
EDIT.- So yeah, chances are she's not virgin. We just disagree on when she lost it