Halo Insider/Xbox Insider-Hub Problem

Hello Spartens,
My Name is B1ackGorn and i got some Problems with the start of Xbox Insider-Hub. Ist saying im under 18 so i cant Play the Game and cant do anything.
I was allready in the Mircosoft Support and its was all okey for him so i wanna ask how can i fix that ? I was Born 1997 so i CANT be under 18 and asking you how the fix it. I got a Invite to the Flight 3 and im kinda late it will be really Kind if i get a fast respond.
Thank you and have a nice fight.

For proff that im the Flight 3 Just say i will send a screen and the Error Massage

If the Xbox app is telling you that you aren’t 18, that says there is something wrong with the account you are using to open the app. I would reach out to Xbox Live Support and ask if they can help you out with that.