"Adult" meaning young adult. He like, 17? Yall I got a million different versions of this guy in my head, so don't even come for me about that stubble cause it's cute and he is still baby >:[
~Headcanon~
Dipper is:
(A little) more confident in himself.
Less self-conscious about his birthmark, and sometimes he'll just let it fly.
Openly obsessed with micropop and 90s disco.
Bi-himself u_u
That earring was not his idea; Mabel fucking punctured him by accident with her sewing kit and convinced him the hole'd get infected if they didn't make it permanent like a fucking demon so now he's just got one goddamn earring that fills him with despair and revenge.
He precious.

The end.