It sounds pretty similar to the magic I'm used to actually, though mine isn't limited to those with elven blood.

Where do you draw the Mana used to power your spells from? Do people have their own reserve of Mana they can draw on from within their body or does it come from outside of them?

And if you don't mind, would you tell em a little about Summon Spirits? [Summoning was something she'd only read but never been able to learn...]