Virgin is sort of a social construct - I understand you mean you never had sex, but that shouldn't matter?
I am guessing you maybe mean you have never put anything in your vagina, such as a tampon or finger. and are scared to do so?
You might have heard some myths about the hymen. If you have one (many people don't) its just some skin vagina. it should have an opening, otherwise how would your period blood get out?
Hymens don't actually break, they can stretch, the the pessary is very small and skinny, and if your slow and careful it seems very unlikely you would change anything about yourself. Put a finger in first, if you can do that, you can use the pessary.