If it helps you feel better about your decision, although there's no evidence that an older child who is still well within the rear-facing limits of his or her seat is actually "safer" facing forward, the official NHTSA guidelines state that children ages four through seven should ride in a forward-facing seat with a harness until they outgrow the harness (at which point they should switch to a booster). And the NHTSA guideline is the most conservative, pro-ERF guideline we have in the US.
I mention this from time to time, but I do strongly believe that part of child passenger safety is teaching our children to feel good about making responsible and safe choices in the car. If your child is resistant to rear-facing and is past the age where rear-facing is even recommended any longer, it does not instill that long-term principle we are trying to teach which later could translate into "Is it really ok to ride home with this friend who's had a few drinks even though Mom says not to but then again Mom's always been an over-the-top safety freak anyway I'm sure a couple of drinks aren't that bad, and he doesn't seem that drunk..." I'm not saying there will be a one-to-one correlation and a child who was forced to rear-face past age four will revolt and start riding home with drunk friends after parties, of course. But a child who grows up resenting the seemingly arbitrary rules enforced by parents which have no basis in any objective recommendation runs the risk of disregarding such safety rules when the opportunity arises.
Obviously the whole equation changes when you have an older child who prefers to rear-face or, at least, doesn't object to it.