I used Ed Hamilton & Co. to book 2 BVI charters. I'll give them an unsolicited plug. The charter rate is the same as it would have been if I booked directly with the charter company and working with knowledgeable people took a lot of the stress out of the trip. We were sailing an O'Day 23 in coastal waters and booked a Beneteau 331 the first time. My wife and I were very comfortable moving up in size and using the boat's systems. We now own an Hunter 29.5 and last fall we sailed a 34 ft on the charter. To a large extent, sailing in the BVI's is like sailing on a really big lake. Everything is line-of-sight and as long as you don't hit a reef it's very easy. Just be certain that you know basic navigation and how to read a chart. Much of the fun is getting a cruising guide and planning your trip prior to leaving.
Looking at your boat, I agree with Pat that you need to get some experience with a diesel, head, and instruments. The sailing will actually be the easy part for you. Find someone with these systems on their boat and crew for them until you feel comfortable with how to use them. If the charter company isn't certain you are qualified (or at your request) they will send a captain with you for a few hours to protect their interests and to insure you have a good cruise. They want your repeat business.
Terry