Scrum half or fly half.
Also, I would seriously advise working on your tackling as coaches don't like a weak tackler in any position. Lacking certain skills you can shrug off and say, you can't expect everyone to be good at everything, but a solid defence relies on the whole team and one weak link will be identified and mercilessly attacked by a good team. It's the one skill you need your entire 15 to be competent at.