You should understand, a female must develop eggs before breeding. Eggs/ovum are easy to feel/palpate.
If a female does not develop ovum, she has no reason to breed.
Your task is to see if she has ever developed ovum/eggs. Heck, with a little experience, you can see it, without problem. They get a "look".
This part may be way off, but no wonder some of you fellas "depend" on brumation and such to tell what a snake is doing. You must not know the basic biological mechanics.
The mechanics are so simple, once you learn them, you do not have to guess.
You should consider, brumation is the suspension of development, thru adverse conditions. Its not a benefitual period. If you have strong healthy snakes, burmation does not harm(if done correctly).
Once suitable temps are allowed, then the snake picks up where it left off. It will restart development.
I guess the that gives some an idea of when cycling could occur. But its only a guess. Cheers