Sex and sexuality are such profound aspects of people's lives and mature relationships that at least for me personally (I'm a few years older) I'd be very wary of being in a relationship with a virgin. The only parallel I can draw is getting married to someone who has never been in a long-term relationship. It's a big red flag, IMO. That doesn't mean I can't respect, on an intellectual level, someone "saving themselves" for marriage, although even that gives me pause. On a very basic level, there is the question of whether you two are even compatable, sexually. Sometimes it's just not there, regardless of how much you like each other. For me at least, that's something I'd like to have a handle on before I walked down the aisle. Having a healthy sex life is essential to long-term relationships, such as in marriage, and IMO/IME it's more likely to happen when both partners have a healthy relationship with, and experience with, having sex. Even just having realistic expectations and being in touch with your own needs is much easier after having had a few sexual partners; these are basic requirements for having a healthy sex life.
Sex is important. I mean, in a very real way it's one of the most important things, I don't mean to discount that. But what is more important, long-term? Giving your future spouse your virginity is a one-time act; really being fully prepared and really bringing the best, most experienced, most-worked-out you there can be, that's something that helps the two of you from day one to forever.