This is my eyes.. it a correct grammar?

"This is my eye" or "These are my eyes" are grammatically correct, depending on whether you are referring to one eye or both.

"It a correct grammar" is incorrect. You should say:

* "It is a correct grammar" (if you're talking about a specific instance of grammar)

* "This is correct grammar" (if you're referring to the grammar in general)

* "This is grammatically correct" (a more common way to express this)

It's important to use the correct pronouns and verb tenses in your sentences.