@Laura2592 An Inquiry for 2021? Man, that is planning ahead. Maybe they wrote the date wrong?
Personally I get bookings that are anywhere from a couple of months to about 10 days ahead. Most are around a month ahead mark.
I guess it would depend a lot on why people are coming. My listing is in a touristy beach town, so people seem to plan a couple months ahead, because they need to line up flights, time off work ,etc.
If you were someplace where a big event was happening, or someone had a wedding to go to, I could see where they might book long before.