Can you see how long you have been part of Halo Waypoint?
I see people with the 3 year badge, and was interested to know when I would get mine, haha.
Must be soon like, I’m sure I’ve been here since the move from the Bnet.
You could always check when your first post was, if you don’t mind digging through possibly hundreds of pages to find it.
You could go to the Advanced Search function when you check all your forum posts and see how far back your date will go.