Hi Linda,
Same holiday I picked for my first JY holiday (last year) and loved it but be prepared its very hectic but worth it because you see so much.
As for money you'll need enough for your meals/drinks (other than breakfast which is provided) and any souveniers/presents you may buy and maybe a bit for a flutter in Vegas. Personally I work on $100 per day (plus excursion money) when travelling to the states but you can get away with less, suppose depends where you eat as costs are about same as here (expensive restaurants or cheaper bars/cafes/diners) or what you spend on souveniers. Of course you can take a credit/debit card as back up which is a good idea.
You'll have a great holiday I'm sure there are so many highlights on this trip.
If you have any holiday specific questions just ask and I'll try to help.
Mick