For all the reasons above I would suggest you wait a few more years for a European cruise.
I don't know where you live, but I would like to suggest a NE/Can cruise out of NY/NJ for the upcoming year. NYC has many kid friendly pre and post cruise activities. The longer cruises often include Quebec City which is a wonderful city with a European flavor and tons of things to do. All the touristy activities are right near the ports so you can avoid any long bus rides.
If you live in Europe, disregard this post.