What would you have done in this situation?

Pub MTT, final 2 tables out of 5, Dealer and SB just moved from other table onto mine. SB somewhat conservative, but can can push on draws or bluffs (but not enough information on the night). Mid conservative but still capable of bluffing, but only when she leads out. I'm sitting in BB. Blinds 3,000/6,000.

Stacks

UTG+1: 25,000+

SB: 15,000

Hero (BB): ~18,000

Preflop

UTG+1 limps

SB limps

Hero 102 checks

Flop

SB: Pushes all in for 15,000

Mid: Looks to be folding, not expected to call (based on her earlier play).

What would you have done here?

EDIT: Thanks for the feedback guys. The SB hand was

And turn/river were blanks.