No Family Center? Uhm, well then I can't help you anymore. All I know is that to join NSFW servers, Discord needs to know your birthday. This would've been a way to cause such a prompt, maybe there are other ways to trigger it, I don't know :(
Well, I can think of two explanations: Firstly, you provided a birthday already, which has some absurd implications; so let's not follow this line of thought. Secondly, your county handles age confirmation differently than most others or porn is banned outright there.
