Villain is a young kid, seems to be a bit on a LAG side. I have $700, he has $1000.

I get AdAc utg and raise to $20, get 4 callers (this is how they play in Miami). $100 in the pot.

Flop Jh8h5c. Blinds check, I bet $50 (too small?), only the villain calls in cutoff. $200 in the pot.

Turn 8d. I check, he bets $120, I call. $440 in the pot.

River 4d. I check, and he bets $400.

Insta-fold or consider calling? AA is just a bluff-catcher here, he is polarized - bluffs or trips/boats.