It's possible for her to be a virgin. I have railed three virgins to date and at the time one was 30 and one was 31.
The 30 year old had been a lesbian most of her adult life and I was her first man.
The 31 year old was a very busy career woman who seriously just hadn't had time to date and had a low sex drive.
Both of them were some of the worst lays of my life. I personally would much rather have a women with experience.
If she is nervous as he|| and/or sucks in bed (as in like bad at it) and/or gets blood all over your c0ck and/or experiences real pain (not pleasurable pain but actual uncomfortable pain), she is probably really a virgin.