Is the word she proper noun?

No, the Word "she" is not a noun, it's a personal pronoun.

A personal pronoun takes the place of a noun for a specific person or thing in a sentence.

The pronoun "she" is takes the place of a singular noun for a female as the subject of a sentence or a clause, in the third person. for example:

The pronoun "she" can replace a common or a proper noun. Examples:

Replacing a common noun: My mother made these cookies, she is a good cook.

Replacing a proper noun: Shirley Temple could sing, dance, and act. She was very talented.

The corresponding pronoun used for the object of a verb or a preposition is 'her', for example:
Marie is coming for a visit. I'll be happy to see her.