Darrell, As for your ship charges your sister is right. The first charge that will appear on your bill will be the gratuities. I believe they are about $10.00 per day so that is $70.00 the first day. All drinks from the bars including juices and soft drinks will be charged to your card also. If you book any excursions on the ship those will be added along with anything you purchase in the ships stores. Also any photos you purchase will be added so you can see how your final bill can quickly add up.
Most ships you can check your bill on the T.V at any time. I recommend that you check this on a daily basis so you do not end up with a surprise on the last day. Also charges can accidently show up on your bill that you did not make. Keep all your receipts. If you feel you did not make a charge go to the pursers desk immediately. Also, if you lose you shipboard card notify them right away so they can make you a new one and keep someone from making charges on your lost card. Remember, you will not be able to pay cash for things on the ship so just handing them your card can easily make the bill climb without you realizing it. You can however pay cash on your bill at anytime by going to the pursers desk. My brother does this all the time when he wins in the casino. He takes his winnings and pays off or pays down his bill. Other places you will be able to use your card is in the spa and you can get cash advances in the casino which will be added to your bill so be careful? I think my highest bill for 2 was $800.00 and that was for an 11 day cruise. We buy more pictures than we buy alchohol. I have friends though that have had a bill as high as $3,000. but I think they bought some jewelry onboard.
Have fun and I think you will be taking more cruises in the future!