Mao struggled at Junior Worlds and seemed to have trouble with her 3A. In the FS, she singled one attempt and doubled the other. She also singled her lutz and could add only a single loop to her second 3F.
Mao does only four jumps: Axel, Loop, Flip and Lutz. For some reason, she doesn't do the salchow or the toe loop at all. If she is starting to have problems with her 3A or any of her other triples, she is in trouble, competitively.
Some have said she didn't want to do JW and didn't care whether she won or not, so that's why she performed poorly. I am not buying that. If she is a true champion, she wants to win every event she enters.
Could she be starting to feel the effects of the puberty bug? According to reports, Mao is 5'3" and during the GP, weighed all of 82 lbs. Common sense says at her age, she will not continue much longer at such a low weight, and she might begin to experience trouble with her jumps as her weight redistributes itself.
I think it is ridiculous to start worrying now if Kimmie can sustain her skating over the next few years. There is no reason to say she can't compete against Mao and Kim because they are so much better than she is, when we haven't seen the three of them compete together as Seniors as yet. Nothing is written in stone at this point. We saw Mao beat senior skaters when she had nothing to lose, with no championship to protect, but we saw her lose her JW title with a disastrous FS performance.