Going Altmer to willingly suffer weakness to magic 25% for 100 magicka. Could be worse. You will need to dodge all spells or else your offense will be stopped because you have to heal and spend more of your magicka, which could have been used to hurl destruction. I think you are spread out too much, and it depends on if you will power level to get +5s every level. Pick two magicka schools, preferably from the same skill so that you will likely get +5 to whichever skill. Huge reasons to be a mage is to get access to spellmaking alter and enchanting alter. Since you're Altmer you already own weakness to magicka ready for spellmaking, unfortunately you have to do those gd recommendations... unless you have the Frostspire ( spelling? ) DLC. If so then you need only cough up a few thousand pesos for those mage tallow candles for your alters.
You went the solid way with the Mage birthsign +30 magicka. Or you could alternately choose Atronach for 50% resist magicka and fill up your magicka with mod methods if you're on the PC:
*Runeskulls mod will give you a chance to find skulls with +1 magicka per second. Allowing you to regain all your magicka with just an hour fast time rest or waiting.
*There is another mod that will silence you for 7 seconds while your magicka replenishes much faster.
*You can replenish all your magicka at once with welkyndstones, but you will need the Varla and Welkyndstones Glow and Respawn mod, or you will eventually use up all welkyndstones in Cyrodiil.
Here is what I think of the magicka schools, just my opinion:
Alchemy - very strong once you can identify 3 ingredient traits. But you must be fine with that horrible interface. You won't be using poisons unless you use a weapon. But there is the shield potion.
Alteration - boring, much like daggerfall. But you can have it be a third wheel with destruction and restoration.
Conjuration - meat shields to draw their fire and hide behind! First it is a simple headless zombie. Then the clannfear. Good if you won't be using a companion mod. Good to pair with alchemy.
Destruction - who doesn't want to make their foe suffer immediately? You need to get to that spellmaking alter asap for the best use of destruction and weakness to magicka. Google Oblivion magicka stacking.
Illusion - I dont' use it because it seems like the "I win" button. And it raises your personality, so it mixes with mercantile and speechcraft. No thanks.
Mysticism - Only good for Soul Trap for enchanting.
Restoration - it heals you and it raises the same attribute as destruction. At first it heals little. Then you will be healing massive wounds with a gesture.
If you are on the PC then you can use Oblivion XP mod so that you can play however you want.