Welcome to the forum. This is mostly quite good; very combat-focused but then, the wizard chassis offers very little in that regard so I'd say it's a legitimate approach. Are you familiar with WotC's Bladesinger? That occupies a similar thematic niche. The main problem you have is at level 6...

Quote Originally Posted by locke249 View Post
Improved Mage Armor
Starting at 6th level when you cast the mage armor spell targeting only yourself, your base AC is 13 + your Dexterity modifier + your Intelligence modifier.
Additionally, when you are struck by a critical hit you may expend a spell slot to reduce the incoming damage by an amount equal to 3x the expended spell slots level. Once you use this feature you cannot use it again until you finish a long rest.

Magical Precision
Starting at 6th level you learn to use magic to attack with deadly precision. You may use your Intelligence modifier for your weapon attack and damage rolls. Additionally, damage from your weapon attacks count as magical for the purposes of overcoming resistances and immunities.
...either of these features, on their own, would be okay. Well, the Improved Mage Armour is obviously too strong, but you could probably get away with something like "when you cast the spell mage armour on yourself, your AC is now 15 + your Dexterity modifier." Conceptually, a defensive boost is reasonable, but what you have at the moment is just too much.

But yeah, you can't have both of these at the same time. If you moved one to another level, you'd have to drop one of the other features. In my opinion, the feature to drop is Improved Mage Armour (and leave everything else as-is) but you may feel differently.