No agencies specialising in this...yet.
It would be amusing (and icky) if there were! Selling virginity is a complicated business, what with having to prove things and find someone odd enough to want to pay megabucks for it (when most people have much cheaper - or even free! - shags and would actually prefer nobody bleed or cry) who wouldn't waste your time or try to not pay by claiming that you were not really as virtuous and pure as claimed - I can't help but think that market is really quite small. Especially if you don't publicise (/embarrass?) yourself in the general media enough in order that your little auction attracts attention from the (three?) potential bidders.
In societies where virginity is still seen as something vitally important, even perhaps the
most important thing a young woman can have, they tend to have a 'handy' system called patriarchal control and oppression in which young virgins are given to men for free via marriage in exchange for keeping her in his house, or cupboard, or whatever. So... you'd have to find a nicer guy somewhere else who just has a virginity fetish, or something?
I think plenty of clients like new girls to the industry, though, so if you're smart and work sensibly and take care of yourself, you can market the hell out of your introduction to the sex biz and profit nicely without having anyone peering suspiciously into your vaginal canal. Plus, it's really nice to lose your virginity to someone you actually fancy (wedding vows entirely optional, though!).
Oh! And perhaps, most important of all, is the fact that virginity is not really a Thing. Well, of course, the first time someone has sex is important.
But
the hymen is not what most people think it is, and you cannot guarantee the bleeding or pain (if anything, that usually comes from the poor virgin not being aroused enough during her first awkward encounter) or even say what "deflowering a virgin" is really supposed to be like.