"adult" is subjective in general, but also by country, by situation, by background, by administrative specifics, etc.
There is no classification "adult" in elite competition skating divisions.
There are two division, "jr." and "sr.", and that is how the ladies are segmented, and how coaches handle the technical and administrative requirements. Eteri has success in both divisions: sr. and jr.
and..Med was not pre-pubescent when she got silver at the Olympics, she was 18, and Zag went through puberty in summer/fall 2017, just before Olympics and her body changes were "officially" noted in winter 2018.
All other "adjectives" describing any condition of the girls are IRRELEVANT.
Eteri also did not have girls that are: "red heads", "taller than xxx meters", "shorter than xxx meters", "from Sweden", "who jump in reverse/clockwise", "who came from pairs or dance", "who insert whatever...".
When one can't accept another one's success, he/she starts applying irrelevant criteria to judge by.
Old joke i heard: A 6 year old jewish boy is applying to a russian school, and has to pass a very basic 1st grade russian language spelling test, consisting for 3 words, to qualify for 2% admission quota. Examiner tells him to spell "cat", he spells "c-a-t". Examiner tells him to spell "dog", he spells "d-o-g". Then to spell "house", he spells "h-o-u-s-e". Examiner is frustrated that he can't fail him, and asks him to spell "eucalyptus"...