Is I an abstract noun

No, the Word "I" is a pronoun.
A noun is a Word for a person, a place, or a thing.
A pronoun is a Word that takes the place of a noun in a sentence.
The pronoun "I" is a personal pronoun.

A personal pronoun is a Word that takes the place of a noun for a specific person or thing.

The personal pronoun "I" takes the place of a singular noun (name) for the person speaking as the subject of a sentence or a clause.

The corresponding first person, singular pronoun that functions as the object of a verb or a preposition is "me" Example:
When I saw the posting for this job, I knew it was right for me.