You and it are both nominative and objective case. Possessive case pronouns are my, mine, your, yours, his, her, hers, its, our, ours, your, yours, their and theirs . They are used to show ownership. Possessive pronouns never have apostrophes, but possessive nouns do. Choose the correct form of the pronoun.
Personal pronouns have what is called case .
Case means that a different form of a pronoun is used for different parts of the sentence. Nominative case pronouns are I, she, he, we, they, and who . They are used as subjects, predicate nominatives, and appositives when used with a subject or predicate nominative. Objective case pronouns are me, her, him, us, them, and whom . They are used as direct objects, indirect objects, objects of the preposition, and appositives when used with one of the objects.