Don't be nervous about cruising alone. I did a little over a year ago (October 2007), and met so many people. Since you mentioned this is your first solo cruise, I assume you have cruised before, so you probably know this, but I'll mention it anyway. You'll probably find that there's so much to do on the ship and in the ports, that you are almost never in your stateroom except to sleep, shower, and change. This is what I found when I went on my cruise.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)