Is the correct grammar it's for mom and me or it's for mom and you?

Both of those phrases are grammatically correct, but they have different meanings. Let us say that you and I are brothers. I am blobbert and you are Harry. Our mom just bought a Pizza. If she is planning to share it with me, but not with Harry (who is going to get something different for lunch, possibly a ham sandwich) then I would say about that pizza that it's for mom and me, so get your hands off of it, Harry. However, if mom is planning to share the pizza with you (Harry) and she wishes to feed me a ham sandwich instead, then I could tell you, about the pizza, that it's for mom and you.