I'm getting my cartilage pierced tomorrow and I'm a bit anxious.
A friend of mine told me they deliberately miss the cartilage and just go through the fleshy-skin part above the cartilage... contrary to what I've heard.
Is she right or not and where exactly does the piercing go through?

Would this be your ear, nose, tragus? The only place we would deliberately stay out of the cartilage is either your lobe or septum, depending on the size you're looking for- otherwise, yes if it is a cartilage piercing involving the ear, yes it is going straight through. It is very quick and most people would describe it as a bee sting type of feeling.