Insecure about my vag?? Tips?

(little bit of background info - I'm pretty much fwb with a guy, we're really close and have a really open friendship and can talk about anything, and I sometimes get the vibe that we like each other as a little more than just friends)

Basically, he really wants to go down on me, and I want him to too, but the thing stopping me is being insecure about him having to see my vagina.

I don't really know why though. I masturbate, I've seen my vagina, and previously I've not had any issue with it. I know all vaginas are different and all are wonderful in their own way, and I know this guy wouldn't judge me or anything because of it. So I don't really know why I don't want him to see it.

Does anyone have any thoughts or suggestions? I don't really know how to solve this.