WHY

Every language has its own grammar. I would say because Chinese has so many characters. You can practice more to master the grammar, speak more and listen more. Will be better.

Actually, like all  foreign languages, the ESL learners need to pick up a total new language from the very first start with total different logical thinkings of forming a new sentence, which makes it so difficult.

Lots of native Chinese speakers don't know much grammar at all, they listen and speak. If you really want to write, you need to know the basics, eg: where you put the time, location, where to locate adv etc.  If you  learn it for communicating purpose only, don't spend too much time on grammar.  As long as you understand each other, that's fine.

there is no grammar before, more people speak and it becomes grammar😄

Chinese grammar is a little difficult, but it's also interesting. I'd like to study with you and feel the charm and happiness of Chinese grammar.