How long in 12/12? If less than about 1 to 1 and a 1/2 weeks...it is very likely a male. Males show much quicker and that looks awfully suspicious. I cannot say with 100% certainty that it is or isn't male. Mostly because this is your grow and you should make the final determination.
That said, I have seen some pretty fat calyx...this is quite questionable though...If it were my plant I might let it go another day or two. I would certainly keep a very keen eye on it though...balls can form and pop very quickly. I would take a look every 6-8 hours and if no visible pistils in that time I would hack it. That is just how I would handle it.
Good Luck and Great Growz