It's possible she might never lay. It's thought that with very controlled feeding and somewhat lower than "normal" temps, females might not make eggs at all or make them very infrequently and not make many when they do.
If she were going to lay you would probably see her get big, probably be able to make out "egg shapes" in her belly and start prowling the bottom of the cage.
If you keep a laying bin in there you can sift through it to see if you find eggs. If there is a plant in the cage with exposed dirt, you should check that too.