So, after deciding that I'd like to encourage ds (9) to read a bit more, I ordered The lion, the witch and the wardrobe without really realising that it isn't the first book in the series - rookie error, I know 
He loves it, and we are really enjoying reading it together. Will it be ok to just continue reading the series from here, or should we go back and read the magicians nephew before starting the horse and his boy?
Thank you!