I don't see a problem with graduating early. And for Pete's sake, DON'T feel like you have to keep taking classes for 4 years.
My suggestion: use the extra semester to travel overseas. There are any number of places that will pay you to teach English overseas, and most require only a BS or BA. You can easily meet your expenses, and have a hell of a time. Countries with lots of open positions include China, South Korea, Vietnam, Taiwan, Poland, Slovakia, Romania, and Hungary. Other countries are possible, if you can find a contact. If you really want to know, I'd be glad to dig up the links I have on the subject. (I spent a semester in China, though I was still an undergrad at the time.)
Naphtali