Heh, takes me back! Was so worried about finding out their sex on my first go...got lucky with my mystery gifted seeds, they must have been feminized because all 10 I sprouted so far all turned out fems.
Give them a good little while and keep watching them. Male flowers develop faster as a they need to pollinate females early so the seeds can develop (ie not 8 weeks into flowering). But you'll have plenty of time to clearly identify a male before it pollinate, especially since you are checking them every day
And if you do have a male maybe consider letting them mate...?
With a male+fem you could make a seed crop and have a lot beans to play with. I also read this helps as seeds made in your garden will be "better suited" for it, and it makes sense though I haven't tried it yet.
But if you are dead set on just growing females or don't have any, I can look into the feasibility of sending you some
Cheers!