My input - I got engaged at 18, married at 19. But that is because I grew up with the "do-not-have-sex-before-you-get-married" idea, and I also wanted kids asap. I now have a kid and am getting divorced.
If I had to do it over again, I would have had sex sooner and not gotten married. I only got married because I thought it was a prerequisite to the things I DID want. Also because my husband really wanted to get married.
I personally don't see why you would get married young if you're poly.
Independent polyperson seeking friendships, in which physical intimacy may or may not develop.
I do not wish to attach to any particular person. My love knows no limits.