Yes it is normal on all cruises for luggage to be collected the night before, usually up to around midnight. You just need a small overnight bag.
Yes "Ingle" is right but there are certain occasions when, provided that you can take your own luggage it can be taken off personally but this privilege is not often granted as it can hinder the process of disembarkation quite considerably. If you are worried about it take the disembarkation tickets you are given to reception and say that you have an early flight and would they give you a priority ticket to get off first. This they will normally do but remember that after your cases have been collected at midnight or whenever that what you have left with you is what you will wear the next day. It has been known for people dressed only in a towel searching through the piles of luggage for theirs....not a pretty sight......Nei.