Here with our hand we obviously raise UTG. When the short stack calls there are plenty of hands he could have. However when we are 3bet the decision is difficult. I can't call since there is another player to worry about and I am not sure if I can stack off with JJ in this position. I don't have enough hands on either player for 3bet stats to be of any value (~50 hands, if I recall right), and I've not seen either 3bet or get 3bet so far. Is there any other option than to fold here?

PokerStars No-Limit Hold'em, $0.25 BB (8 handed) - Poker-Stars Converter Tool from FlopTurnRiver.com

saw flow

CO ($25)
Button ($25)
SB ($19.25)
BB ($50.30)
Hero (UTG) ($47.30)
UTG+1 ($36.90)
MP1 ($6.70)
MP2 ($5.15)

Preflop: Hero is UTG with J, J
Hero raises to $1, 1 fold, MP1 calls $1, 3 folds, SB raises to $4, Hero... ?