Are you confused about when to use me vs. I? The two are not interchangeable. It's something that confuses many people.
Me is a pronoun that is used as an object of a sentence. For instance:
Grandpa took me to get ice cream. (Grandpa is the subject, and me is the object in the sentence.)
I is a pronoun that is used as a subject of a sentence. For instance:
Grandpa and I went for ice cream. (Both Grandpa and I are subjects of the sentence, and went is the verb.)