Main Similarity and Difference
'She', 'I' and 'me' are all pronouns, but there is a significant difference between 'she' and 'I', and 'me'. The first two are subject pronouns, and the third one is an object pronoun.
Coordinated Subject or Object
If we have a combined subject coordinated with the word 'and', we must follow one simple rule: the two words coordinated by 'and' must be of the same categories, i.e. :
- (subject + and + subject) or;
- (object + and + object)
In this sentence, we have a combined subject (or coordinated subject) which is two subject pronouns joined by the coordination conjunction 'and'.
She and me are more like best friends than mother and daughter.
'Me' Is Always the Object
Now, 'me' is NOT a subject pronoun. It is an object pronoun, and it can only be used in the accusative case. So, you cannot use 'me' in a subject position in a sentence. 'She and me' is not correct, because one of them is a subject pronoun and the other is an object pronoun.
You cannot use 'object and subject'. Only use 'subject and subject' or 'object and object.' Therefore, 'she and me' is not grammatically correct.
But this example is correct:
I can't believe you would do that for
Her and me are both object pronouns, therefore they can be coordinated with 'and', and come in the position of the object of preposition.