Its a familiar considered as a Mage?
No, a familiar is not a mage. A familiar is just a regular creature which can cast spells. If not mentioned otherwise, you need to plan its spell during the planning phase. So, you will end up with two planed cards in your hand for your mage. Additionally to that, add a faced down card on your familiar; so it can cast that card later during its action.
Here are the most common queries regarding Mind Controlling familiars:
From the FAQ
If you take control of a familiar you are legally allowed to control, you take control of any spell which was planned for it to cast (unless that spell is restricted from your Mage class or school, in which case it is immediately returned to the owner’s spellbook instead). You can use the familiar to cast that spell, and you will have control of that spell after it is cast. Alternately, you can change out the spell on a future planning phase, at which time it is returned to its owner’s spellbook.
From the FAQ
The Forcemaster cannot cast Mind Control on Huginn, Raven Familiar because it has the Arcane Mage Only trait.