After being in Pupil mode for a while you get to change classes, it just matters what lvl you are.

Pupil- Change to Mage at lvl35 or wait for Shaman at lvl40

Shaman- Change to Druid at lvl100 or wait for Mage Knight at lvl120

Mage- Change to Mage Knight at lvl120 or wait for Sage at lvl130

Respect Scale/Specialize Chart-

1.Sage= Specializes in- Light, Natural Magic.
2.Mage Knight= Specializes in- Light Magic.
3.Druid= Specialzes in- Dark Magic.
4.Mage= Specializes in- Natural Magic.
5.Shaman= Specializes in- Dark Magic.
6.Pupil= Specializes in- Natural Magic.