I would also go with #1.
We took a smaller 3 day cruise on our first one, then jumped to a 7 day cruise on the next. I thought the 7 Day was just about right. It went pretty fast, there was plenty to do and you only get bored or don't have fun if you let that happen. We even had a bad experience on one of our 4 day cruises, but still decided to make the best of it and had a good time and would do it again.
As was previously mentioned Day #1 and #7 are half days or less at best so you really have 5 as full days.
Have fun on your first cruise and enjoy the sites!
Visit us at:flyingarizona.net
~ Future Cruises ~
~ None ~
~ Past Cruises ~
RCI - Vision of the Seas - 2003
RCI - Monarch of the Seas - 2004
NCL - Norwegian Sun - 2006
CCL - Paradise - 2007
CCL - Splendor - 2010
CCL - Spirit - 2011
CCL - Inspiration - 2011