Your pass will still work. Magic Bands for Annual Passholders aren't ready yet. They're only issuing them if you have a resort reservation.
Did you exchange it for one of the RFID cards? The hard plastic ones? That will allow you to use the new entry gates with the little light up mickey heads.
I am an annual pass holder and chose to take the magic bands, we just returned last Monday. If you decide against the band, just change your ticket in at Guest Relations for the RFID Cards.
If you have an upcoming resort stay, MagicBands can do more than just park entry. They can act as your room key, room charging (with CC on file with resort), PhotoPass and FastPass+.