My family thinks you can only know your sexuality if you've had sex with all genders

I recently had a conversation with my family about this. I was told there's no way (even though I'm 31) that I could be panromantic and asexual unless I've had sex with all possible genders.

I'm a virgin, for what it’s worth. I've never had sex and have only dated casually (because thus far all dates have expected sex). How do I explain that I can be pan without needing to force myself into sex?