As you say this is not a neighbour you had spoken to, she either got the impression from seeing other neighbours parking in your drive, that it was a free for all and perhaps assumed you did not have a car, or, perhaps was talking to another neighbour about having someone to stay and not knowing where he could park, and the neighbour told her that you allowed people to park on your drive, omitting to mention that you must not be blocked in. Even so, she should have apologised and been more helpful when you went to complain - I imagine she felt guilty and bad about telling her guest it was ok to park when it wasn’t. This young man should not have been angry at you - he doesn't sound very nice, was probably cross with his host who seems to have been afraid to upset him in spite of his being young. Perhaps it is a loved relative who visits her rarely on sufferance and she is afraid he won’t want to come again.
Why not knock on neighbour’s door, say let’s be friends, and invite her round for coffee where you can explain the situation and laugh it off. Start the New Year on a good note.