Your nitrates should definitely be under 20 ppm for rams, whoever tells you otherwise is crazy. You don't need a low GH for rams either. My GH is 300ppm or more, pH is 7.8-8.0 and my rams spawn for me all the time. One of my last batches I had about 125 eggs or slightly under but there was only a single unfertilized egg, so pretty much 100% fertility in those params.
Young fish, but not hard to sex. It's definitely a female. First, you can see that the pelvic fins don't extend past the start of the anal fin. This method has been bulletproof for me in sexing rams. Second, the first few dorsal rays are the same height as the other dorsal rays, indicating female rather than male, which would show prominent 1-3 dorsal rays. Lastly, look just forward of the anal fin. Notice anything? I see the ovipositor. Provide her with a male of similar size and my guess is she plumps up and drops eggs within 3 weeks.
EDIT: I just noticed that the fish in the bottom picture looks different than the one in the top picture. It actually looks like it's a male in the bottom picture. I'm 100% certain that it's a female in the top picture. I'm also 90% certain that it's a male in the bottom picture. Isn't this the same fish??? I noticed because the amount of yellow on the fish in the second picture seemed to extend further back thatn that in the top picture. I couldn't see the pelvic fins so that was my backup method in sexing the fish in the bottom picture.