Ahoy, Joanna!
I think Early to mid-March will be a perfect time for you and your sister to try your very first Disney Cruise Line vacation! There are less children out of school at this time, so you might find that there are more adults onboard at this time.
I would also suggest that you consider either the Disney Magic or the Disney Wonder for your first ship. These ships are the smaller of the Disney fleet, but are still as gorgeous and wonderful as their larger sisters. I think the smaller ships feel more intimate and less crowded. My first cruise was on the Disney Magic, and it is still my favorite ship!
Be sure to plan to attend the Broadway-caliber shows in the amazing Walt Disney Theatre. The Disney Magic has a brand new show,
"Tangled: The Musical", coming in November. I can't wait to see it! Also, you might want to plan to try a nice leisurely brunch at the adult-exclusive restaurant, Palo. This is one of the highlights of any Disney Cruise Line vacation for me.
I know making the decision to cruise is a tough one. Please visit us again here at the Disney Parks Moms Panel to ask us more questions that you have about planning a Disney Cruise Line vacation.
Happy Cruising, Tracy V.