Seven years? Kid, seven years is nothing. How old are you, fourteen? I just published Nobots last month, have been working on it since 2009. I'd have a two year copyright.
The Paxil Diaries aren't even in print yet but the copyright would have expired.
Asimov's Foundation trilogy was out for ten years before Asimov made a dime from it.
The present copyright term is way too long and harms creativity and culture, but your length is equally ridiculous. Make it twenty years, same as patents.