I always want to participate in these, but don't like making "best of" or "favorite" lists. 5 could be 1 and 4 could be 3. 1 could be 2. I could go on. 3 could be 4. It's maddening. I hope some day can deal with my mental problem.
If you want to do it, go for it. You can edit your list throughout the month as long as you quote yourself. Some users have changed their lists 3-4 times in a month.