Not all people have a spirit animal and no people have an element.
You should stick with basic concepts before you move on to specifics, that way you don't start chasing after made-up specifics.
I suggest True Magick by Amber K. It's kind of Neo Pagan since Amber K herself seems to be Wiccan, but the book itself espouses no religion. It does a pretty good job of covering complex concepts in a way a 15 year old could understand.
It's relatively common and you can buy it in the SoM store for less than $15.
You can also read it on-line at scribd.com, but it doesn't have the best of interfaces. Don't even try reading it on an iPhone.