My initial thoughts on Christabel part 1

This must be near a castle in a forest, it's late because an owl is hooting. This man has an old toothless dog that howls at something sixteen times. Could it be the ghost of his wife? Now the true setting is shown: its a cold night but the moon is out and this lights up the sky which is thinly vealed by a sheet of gray clouds. It is the month of April. This seems really eerie, well this poem is defiantly dark. Why is this woman in the forest? This lady is in the forest praying, but then she was scared? Christabel was scared by a tree?  No, it was what was behind the tree, it was a ghost. Was the ghost trying to frighten her?  When Christabel says "Mary mother, save me now!" that tells me she is scared. Was Coleridge writing a creepy ghost story? The white lady says to have no fear, so this lady is good. This lady tells Christabel about how she came to be a ghost. She takes this lady to the castle? So she lets the white lady in, then Christabel gets possessed.  Whats going on? Then she gathers herself and then shes fine.