Here is what I can tell you from experience once you feel follicles of the size of a quarter which is what you are describing, the female do no longer need to be paired however she is still at risk for re-absorption.
At 25 mm you are still a little way from ovy, follicles are golf ball size right before ovulation and if it has been 3 weeks since palpating chances are she is there.
Now as far as what to expect well first follicular development take anywhere between 4 to 8 months, during that time your female will migrate to the cool side and spend most of her time there, once she ovulates she will move back to the warm side, stop eating (if she has not yet) and have a pre-lay shed 14 days after ovulation and lay her eggs on average 45 days after ovulation.
If you are observant even if it's your first year you should know where she stands and ovulations are really hard to miss.
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