It sounds fab but just one word of warning - check that it really is "luxurious" - the rise of cut-price cruising (in Europe, I think the Australian market is different) has given rise to a number of passenger claims, caused mainly I think by the discrepancy in expectations - people pay 500 quid and because it's a cruise, they expect the QE2. In general, you get what you pay for, so you might want to check out that it's really the bargain it seems.
if it is, GO FOR IT!