If you ain't comfortable on two wheels no more, it's the absolute right thing to do. Don't wait till pride kills you or your old lady. Trikes may not be the coolest thing in the world if your used to two wheels, but it's way cooler than wrecking cause you ain't steady on top of your game no more. In the end, half a sandwich is better than no sandwich.
Good points for a trike:
You don't have to worry about putting your feet down
More storage space
Stable on gravel roads
Looks cool and gets attention
Easy trailer towing
Cons:
Watch the rear fenders around gas pumps
Do not put feet down. Ouch!