What counts as "young"? I've found no age cut-off in the membership materials for this well established organization. The webpage explains that
Except for professors the Association – as it is stated in its Statutes – is open to all young legal historians. This exemption has been made to provide the possibility for young legal historians, who cannot present their ideas on other conferences to share their research results and have it discussed with other legal historians but without the watching eyes of tutors and mentors. Professors and institutions are only welcome as sustaining members.
Call for Papers for the XVIth European Forum of Young Legal Historians, 24th-28th March
2010 in Frankfurt am Main