Changed how elf magic works

I have to admit I haven't even played the game yet but decided to house rule elf magic usage. My gf chose elf character and she's beginner in this kind of games even though she's been a gamer past 10 years so. Anyways.

In D&D 3.x she had sorceress character. Sorcerers are like mage but more simple and versatile to use in cost of spells collection. That's how I saw elf in Lamentations but found out they were not. Anyways, here's my concept. It is not ment to be cool for you guys but I wanted to share it here because you are experienced in the rules and can tell me if I broke something really bad (game balance down the drain). So here it is. And sorry for my English.

Elf magic is inner power rather than learned and studied art. Elf magic's origin is in their soul and as they grow more experienced more powerful their magic abilities become.
Each level elf learns new spells so his spell list is as shown in spells per level. Once spell is learned it cannot be forgotten or changed as it is part of elf's soul.
Elf doesn't have to memorize spells but he can cast as many spells as their combined level is equal to character level in 24 hours. One hour rest per used spells levels is needed to recover and be able to cast again.
Elf learns one spell in his first level. Different from magic-users elf doesn't know spell "Read Magic" automatically. Elf cannot use magic books, write spell scrolls, create potions (OR YES FOR POTS?!) or create staffs or wands. Some elfs can cast scrolls as magic-users if they have chosen "Read Magic".

So elf can shoot all the spells he knows without memorizing them as long as used spell levels don't go over character level in the cost of how many spells elf can possess and that he cannot create stuff.