@Cathy224 you are clearly a very thoughtful and considerate person to be thinking of the existing guests and how they might feel about seeing a lower price!
If someone asks / complains about that, let them know that they paid your *normal* price and (because they booked early) got to pick and choose their travel dates with full freedom.
Travel pricing often includes last minute discounts, but there are costs associated with arranging things last minute: could they get a flight at the last minute? How much would last minute airline tickets cost, even if they were available? Could they get time off from work without much warning?
The reason rooms booked early might cost more is simple: they are worth more.
Personal story: I happened to have some leftover nights at a very nice timeshare in Manhattan that I had forgotten about. They were about to expire. I offered them to everyone I knew (relatives, friends, relatives of friends, friends of relatives) for FREE.
No takers. No one could arrange travel at such a late date.
Imagine: a room that normally costs $400/night had no takers at $0 because of the last-minute nature of the travel.
Rooms booked early are just worth more.