My Films Age Rating

I decided that my films would be rated a 15, because my film will contain drugs,  strong language violence. My film would be unsuitable for children under 15 to watch. My film wouldn't be a 12A or 12 because it contains drugs and a lot of strong language at 12 there can only be a bit of bad language. My film won't be needing a 18 the reason for that is there is no nudity and sex in this film so the perfect age rating for my film would be 15.