If Zelenskyy passes that he knows that would be a death sentence. I think that's a red line for Ukrainians. That's why it has been a resounding no from all levels of the UA government (the only people for are the rabid nationalists and the neo-nazis). If they start mobilising 18yos there will be a coup. Because mobilising 18yos, means potentially mobilising 17, 16, 15yos, as in those current age groups might be old enough for mobilisation in the near future, depending on how long the war lasts.

It'd be a coup or a mass exodus, any teenager and their mother would be running for the border.