Should I Get All the Shrines Before Ganon?

There are 120 shrines in Breath of the Wild, and by no means do you need to complete them all before fighting Calamity Ganon.

How many shrines do you need to fight Ganon?

Chances are, you won't have found every single shrine before beating Ganon. There's 120 shrines to find in the game (with more coming in DLC). It's well worth tracking down all 120 shrines as each differs greatly in premise and difficulty and they're all absolutely brilliant.

Should I do all shrines before divine beasts?

Like anything else in Breath of the Wild, you can tackle the divine beasts at your leisure, visiting them in any order you want at any time you want. If you want to finish all 120 shrines and get the Master Sword before cleansing a single divine beast, nobody is stopping you.