Being a mage is a fun way to play.
I hope your race is Breton or Altmer, they have the best mana race prerequisites.
Go and find the college of Winterhold and pass it first, you will meet people that sell spells who will come in handy. Also items you get doing the quests are good for a mage.

During lvling best to go with Destruction, Alteration (if wearing robes to protect yourself, Mage Armor and Atronarch are useful) or Illusion (if wearing armor - Invisibility is useful, while Mayhem and Hysteria are fun to watch ) and Conjuration.

If wearing armor I advise you to activate the stead stone (west of solitude) so you can move like without armor, if wearing robes I would go with the lord stone (near dawnstar) to protect you from dmg.

enjoy