YPG, the militia formed during the seperation of Rojava from the Syrian government, have been accused by Human Rights groups of using Child Soldiers.

Correct… and notably, unlike the other forces around them (Syrian dictatorship, Turkish-sponsored islamists, ISIS, etc) they responded to the accusation within a month:

In June 2020, United Nations reported the YPG/YPJ as the largest faction in the Syrian civil war by the number of recruited child soldiers with 283 child soldiers followed by Hayat Tahrir al-Sham with 245 child soldiers.[141]

On 15 July 2020, SDF issued a new military order prohibiting child recruitment. The NGO Fight For Humanity conducted multiple training sessions with hundreds of SDF commanders about the UN-SDF Action Plan To Prevent Child Recruitment, and distributed informational posters and flyers about it written in both Arabic and Kurdish, as part of an ongoing educational process. Syria-based researcher Thomas McClure observed that “SDF are less likely to engage in such practices than any of the other forces in Syria, but seek to hold themselves to a higher standard of accountability and human rights.”[142]

On 29 August 2020, SDF announced the creation of a new system that anyone can use to confidentially report to specialized Child Protection offices any suspected case of child recruitment, in accordance with the action plan that the SDF signed with the United Nations in the summer of 2019.[143][144]