Although item of advice for writing is to not introduce too many things at one time.
Please don’t introduce all 13 gods of your religious pantheon in the first chapter.

...I’ve seen stories like that and it rarely comes off well. Pick one god and introduce them in one chapter. Later on, if you have to introduce more, then introduce another one in later chapters but certainly don’t introduce them all at once.
Likewise, don’t dump your entire magic system in one chapter. Explaining how all sixteen elements work is not a good idea for a text wall and please don’t do it.
Don’t make up too many names. Like don’t covert Monday => Tiermarsh and Thursday => Ganash and expect readers to be able to follow your fantasy language.
While JRR Tolkien is cool, for most people, it’s a bad idea to copy him, and at best it will just look like you’re attempting a poor imitation of LoTR.