Welcome to Cruisemates!
Although you posted under the HAL forum, I would suggest not taking your daughter on HAL for your first cruise, even though their private island Half Moon Cay, is gorgeous. Depending on the timr frame, kids of any age could be scarce and I think there are better options.
I would suggest taking an RCI ship, one that goes to one of their private islands, Labadee, or, Coco Cay. Ladadee has all the bells and whistles to keep an 18 yr old in teen bliss, and, you lounging on a chaise taking it all in, reading a good book, and watching her enjoy herself.
The 2 newest ships, Allure or Oasis, have so much both of you can do together, or, on your own,,as does the Freedom class..,smaller, but, still filled with parades on the promenade, cafes and people watching, and, tons of entertainmant options.
The best advice I can give you is: to talk to a cruise specialist travel agency. Explain what you want out of this cruise,and let them match you to the best ship for both of you.
Anything you need, we are here to help.
Also, make sure you take out travel insurance, for peace of mind...