Those are so pretty! 6 of mine I just got will be 24 weeks tomorrow, but I don't think it'll be that soon for mine.
You never know. Out of the blue mine started squatting when I would approach. One day they would run away and the following day they were squatting and a few days after that they were laying. To me, for an EE, the best way to tell if they are getting close is if you witness them squatting (submitting) and sticking their wings out to their sides when you lean down to pet them. None of mine has combs that changed color or got bigger so that was not a good indicator for mine. Good Luck!