Party 30+3: Heads up with a piece of the flop
 

5 players left, I'm shortest with 520. Villain has 1500ish.
Level:4 Blinds(50/100)

** Dealing down cards **
Dealt to Mulperi [ 9h 7h ]
kard13 calls [100].
3 fold
Mulperi checks.
** Dealing Flop ** [ 3d, Td, 7d ]
Mulperi checks.
kard13 checks.
** Dealing Turn ** [ Jh ]
Mulperi is all-In [420]
kard13 calls [420].
** Dealing River ** [ Js ]
Mulperi shows [ 9h, 7h ] two pairs, jacks and sevens.
kard13shows [ 9d, Jd ] a flush, jack high.

I checked the flop with the intention that if he bets, I'll fold. Is this too weak?