Article 22 sec 7 of NMA says otherwise:
Part-time employees hired after August 1, 2008 will receive holi-
days, personal days and option days provided by any applicable
Supplement, rider, or Addendum no earlier than after one (1) year
of active employment. This provision supersedes any provision on
the same subject in any Supplement, Rider, or Addendum to the
extent the provision makes holidays, personal days or option days
available earlier than after one (1) year of service.
If you're getting it earlier, good for you,, but I wouldn't plan on that lasting forever.