Welcome aboard, Matthew! Since you've already sailed twice before with Captain Mickey, you know how much magic and excitement is in store for everyone in your family on this vacation!
Disney Cruise Line has the most wonderful Youth Clubs at sea. If you haven't sailed in awhile, perhaps the last time you did, your children were both at the ages to participate in the Oceaneer Club and Oceaneer Lab. My kids have always loved those clubs! But, now, your daughter is able to join in on the fun at two different clubs:
Edge, the tween club for ages 11-14, or
Vibe, the teen club for ages 14 to 17. There is a strict upper age limit, so I'm sorry that your 14-year old daughter will not be able to participate in regular programming at the Club and Lab since she's two years older than the 12 year old limit. However, during Open House hours, anyone can go play in the Club and Lab, so she and your son can check out those spaces together with you during those hours.
I'll let you in on a little secret: If a child is almost 11, he or she is able to participate in the tween club, Edge, with a parent's written permission. My daughter got to do this on our last two sailings, as she was ten, and ready to move on to the tween activities. We stopped by during Open House that first day and the counselors there were happy to sign her up with my signed permission. Just know that at Edge and Vibe, kids can come and go as they please, so parents are not notified or required to check them in or out as they must do at the Club and Lab. As long as you're comfortable with that, your son can hang out there, as can your daughter, if they'd like to be together in a club. I do hope your daughter checks out Vibe too, as it is certainly the place to go for teens onboard!
Have fun on your cruise, Matthew!
Marcy