Tough live spot pretty deep with 77

[MJ of Poker]

Game is 5 handed and blinds are 300-600, we all have around 120k.
I open to 2100 from Co with 77, BTN (real estate whale) calls, sb folds and BB (very tight) reraises to 8100. I call and BTN calls.

Flop:
AJ7 (2 hearts)
BB leads for 19k, I raise to 45k, BTN calls (?) and BB tanks then shoves...
(time to fold???)

any comments r appreciated, thx