Normal. My DS started going right to left and from the bottom right corner up to the top left. It will come right as he gets better at it.

DS's kindy teacher said it was to do with the brain cross-over - it is natural to start on the right side when using the right hand, especially in kids that skipped crawling like my DS did. You may be able to help him by doing gross motor cross over activities e.g. getting him to touch his shoulders with his ipsilateral hands, then contralateral, repeatedly as a move to a song. A lot of the actions to songs they do at kindy are the basis of writing.