Made a silly mistake, took Dunmer with Attronach . Will my mana pool be ok ? I mean with levels and better gear. Im lvl 5 now

Just tell me if its playable or ill need mods .... because I see spells have costs 200-800 mana and I have 260

It's playable. The Attonach birthsign provides the largest boost to mana of any birthsign and the stunted magicka can be overcome through alchemy, plus at higher levels you get a lot of magic thrown at you so you can absorb quite a bit.

The mana cost for those spells you are looking at will drop dramatically as your skill in the various schools of magic increases. 260 is plenty, plus you can increase it even further by taking attribute bonuses to intelligence as your character levels.

What the Khajiit said. Also, don't overlook the fact that Conjuration and Illusion provide alternate (and often economical) means of fighting enemies. Destruction is never the only approach (and it's often the worst way.)

Also, don't forget that you can fashion your own spells, and that spells that work over an extended duration are cheaper to cast than those which do all their damage at once.

Unless you plan to play a pure mage, a Dunmer / Atronach combo is exceptionally powerful as a melee or melee/mage hybrid. 50% spell absorption + 75% fire resistance means you'll be able to mostly laugh off any sort of fire damage, which is convenient if you plan to visit the planes of Oblivion much. 10 point racial boost to Destruction + Major Skill + Magic Spec class means you'll hit Journeyman level pretty early and have access to Weakness to Magic, which is a significant force multiplier when used properly. +10 racial to sword, which is the other half of Spellsword.

I can't actually think of a better race and birthsign combo for a Spellsword, in fact. Breton maybe, but you'd be more spell than sword for a while until you built up the Breton's weaker combat skills and stats. Altmer would give you the highest Magicka pool but you're weak to three damage types. Can be overcome, but takes some specific strategies.

So not only is it playable, it's probably optimal for that class. I am assuming you are referring to the built in class of Spellsword.

You shouldn't have to worry about those towers in Oblivion gates "Hit me again! Some more!"

As the other said, yeah, you should be fine. Actually not a bad combo at all. Spellsword so rely on swords to mop up rather than destruction. Although if I may suggest, the Destruction school features highly economical "Weakness" spells that my current Dunmer Spellsword uses to great effect. I think there's even a thread not too far down about them...

You can enchant 8 items of apparel and a shield with Grand Soul Gems to "Fortify Magicka 24 points" each. Four potions made from void salts and water hyacinth (other combos work too) gives you another magicka boost and massive restore magicka for the duration. An Orc who can barely spell can be a powerful spellcaster.

Wouldn't that be a "misspellcaster"?

Magicka. It′s called Magicka.

And yes, it′s playable