How many weeks has it been on 12/12? It looks like a very well watered, well nuted plant. It looks, (this is me being serious this time) like a Sativa heavy hybrid. Those branches are definitely Sativa, but the leaves are Indica--I have the opposite on my one Bubblegum. Long, slender sativa leaves but built like an Indica.
It's tough to tell, but with the growth you have, what I think, just guessing here, is that your light source is in the green/blue spectrum and your soil is in the Nitrogen heavy range. YOu're not using LEDs are you? That's great for veg, but you HAVE to switch lights into an orange/red spectrum, unless you are using floros or natural sun, which have them all in lower levels. Either way, flowering plants need more phosphorus and potash than vegging plants. Nitrogen is for babies...That might be what is slowing your flowering cycle...you are still treating them like veggies except for the hour cycle, and they are having trouble reacting.
Like I said, wait a week or two before really freaking. Check out picks of males and females, and use your judgment. Plants do what they do. They just take more time than you think they should. Based on those photos, my gut tells me that you have a female, but MILF is right, those shots don't really show much. Worse case scenario though, take care of it and learn how...even if you get jack shit from your grow, you'll still learn. I have killed more plants than I've harvested, but every time that ratio gets smaller because I'm learning.
I feel bad trying to give advice on this site, due to how many real live old school growers here that know WAY more than me, but take my advice for what it's worth as someone who is in the same boat you are, and has learned from really depressing mistakes...Just keep growing.
If you have other females around, do the rational thing and separate this one until you know what's up. If it's your only baby, then watch her, and dude, dude, dude, I cannot stress this enough--if it's the only one and it's a male, it won't take too much time to mature and produce pollen. I would love to get my hands on some pollen now, whereas when I started, I avoided it at all costs. You want to produce crops, you need males at some point.
Still, like I said, looks like a girl who is taking her time flowering, but don't quote me on that.
God bless em for getting me high.