Welcome Aboard, Aimee!
One of my favorite things about Disney Cruise Line is the amazing food. The restaurants have a wide variety, to meet the needs of many. And, DCL doesn't limit who gets to order what when you go to your dinner in the
main dining rooms.
So, to answer your question, yes, any of your children will be able to order off the adult menu. Adults can order off the kids menu. Anyone can order a combination of kids menu and adult menu items (that is what my 11 year old almost always does, she loves macaroni and cheese and a steak).
A cruise is also the perfect time for everyone to try something new. Your dining team will probably tell you that you should try things, and even if it wasn't what you were planning to order, you can order it in addition to your meal. Our children have had the opportunity to try escargot, lobster tail, and wild boar, most of which we would not have actually ordered in a restaurant at home.
And the best part of the main dining rooms on a Disney Cruise Line vacation is your servers. They travel with you to each of the restaurants, and get to know your family. By the second night, our assistant server usually has our drinks waiting for us (based on the previous night) and is standing by, waiting to assist with the cutting of the steak! They will give your kids Mickey-shaped ketchup, bring special food if you commented on how much you liked it, and entertain the entire table. Our children remember our servers from every cruise.
I hope this helps with your cruise planning! Please come back to the Disney Parks Moms Panel with more cruising questions as they arise.
Happy Cruising, Tracy V.