immalemon,
I guess mentioning that you are setting sail on the day that the Titanic sank wouldn't make you feel better would it?

Okay, so technically it hit the iceberg on April 14th but it sank around 2:20am on the 15th.
Seriously, I was married on the 15th of April in 2000 and we went on a three-day
DCL trip as part of our honeymoon. I was worried about the same thing that you were! About 1 hour into the sailing though, I completely forgot about it.
First of all, the ships are never that far from land when they sail. Even if you can't see it (and sometimes you can!), it is there. Most countries could have boats out there pretty quick if need be.
Secondly, there are ships all over the route that the Wonder takes, so even if there was a problem, another two or three boats could be there in a matter of a few minutes. Our communications are much better than they were back then so there wouldn't be any ships that could claim they didn't know what was going on, like the Californian did while the Titanic was sinking.
Lastly, The Carpathia, the ship that finally came to the Titanic's rescue maxed out at a whopping 17 1/2 knots. The new ships can go faster now and can get to a rescue sooner.
Relax and enjoy! By Dinnertime, I bet you will be much more comfortable!