There is a diagram of the belt routing on the underside of the hood. I have made the mistake of looking at it.....then installing the belt.....to find that it did not fit.....a CLOSE inspection of my work....and I found that I had not followed the correct routing. Just one wrong turn....and it will seem too long, or too short. I am guessing that you may have done the same thing.
One thing to keep in mind while you are putting the belt on, smooth pulley, smooth side of belt, grooved pulley, grooved side of belt.
Autozone should also have the correct routing for the belt under vehicle repair guides on their website....
www.autozone.com