I'd fold here for a couple of reasons. First, there are two shorter stacks behind you, so they could very reasonably call you with any ace or any pair higher than 6. Your M is pretty low but with the shorter stacks behind you, you shouldn't be that desperate yet.

Second, you'd be pushing into the big stack's BB, and he'd call you with the same range as mentioned above IMO. Of course, reads would help, particularly that of the BB, but with no reads, I'd fold hoping to pick up a monster before the blind comes back to me.