Are there any H-scne dialogue changes whether she's a virgin or not?
No, it's ambiguous because the game technically can't be sure whether any given instance of sex is defloration or not.
The difference (which will be more obvious if you pick one in the gallery) is that H-scenes have two possible setups, one which happens in-game when Erica's lewdness is <100 (if my memory is serving me well), or >100.
<100 will be resisting sex (and you can headcanon whichever one you encounter in-game first as defloration; that's what I did first time not knowing any better), and >100 is liking it, hence the corruption tag.
There should be two items you can buy in shops that raise or lower Erica's lewdness by 100 points, basically making them a switch between the two types if sticking with one or the other is how you like it.
Also, don't know if this was made clear so just making sure, but when fighting a boss you either have the option to beat them normally with no H-scene, lose the fight and have a rape variation of an H-scene, after which you can try the boss fight again in-game with no real penalty, or agree to have sex and skip the boss fight, which has a different scene premise but the same CG (so there will be two of each CG in the gallery).
Cheers!