Preflop
I think, this is a fold or 4-bet spot with the 21BB stack in between you and the 3-better. The issue is, when you just call, BTN is also going to either call or jam, and neither of those outcomes are great for you. At 2NL there is not much light 3-betting going on, so I think, its fine to just fold.
Flop
It sucks, that he almost potted it, and its kind of close. You could be dead to JJ, but if he has a hand like QQ-KK, your odds are just good enough to take a 1-card draw, if you factor in implied odds. And he is probably not bluffing considering, that BTN has half his stack in the middle already. So yeah. If I got here, I would probably also call and hope to bink it on the turn.
Turn
Now its a pure math decision, since he have moved all in. Work off the table with a free program like Equilab to get the answer for spots like this. You had to call 58,5BB to win 221BB, so you needed 26,9% equity to break even. Against JJ+ you had 20,08%, and this is even ignoring the fact, that BTN will occationally win the main pot. Clear fold.
__________________
|