The answer to this is nuanced — it depends on the program/organization. Standard leveling is Novice/Rec, D, C, B, and A. StinkySocks leveling runs 1–9 (9 being the highest); read more here. The Belmont Women's Hockey League has its own leveling system that provides more granularity for lower-level skaters, ranking skaters 1–9, but this is distinct from the StinkySocks leveling system; read more here.
Right now, with more limited summer programming, a great place to start is the StinkySocks Skills Clinics (Mondays & Fridays, Somerville) — co-ed, no multi-week commitment, and no jersey required. Or come to the Women's No-Commitment Game in Belmont, also commitment-free and welcoming to a range of skill levels (jersey purchase required in advance — visit StinkySocks.net). Warrior Arena also runs Women's Skills year-round for a range of skill levels.
Most of the beginner/learn-to-play programs are open to those still learning basic skating skills, especially the Somerville and Cambridge LTP programs. Check out our Programs & Calendar page for the full list.