I would say there's a good chance it's male, but I wouldn't be certain enough to chuck it out without flowering it to be sure
You haven't had any new growth in a month? Then you'd have more to worry about then sex. If two white pistil aren't coming out then it's not a female. If there is alittle ball there with no white hairs and it appears to have a tiny little stem on it, then it's a male.
3 months veg and still no definitive preflowers??? I would just take a cutting and stick it under 12/12 at this point if you're not planning on flowering the whole thing soon, so you know for sure. My current grow
I have two of the same age and have already shown female flowers, this is the largest and thickest of all.