@Yadira22 As it's been pointed out, I think it really depends on your area! 6pm seems late to me, but you should set what works for you and as long as you stay booked, I wouldn't worry about it!
For my area, I've found guests are more in need of flexible check-in time, than check-out. Most of my guests are traveling by car with a travel time of 2-6 hours.
On average, my guests check out an hour or more before check out time (11am), but check in times vary widely. My official check in time is 3pm, and while I don't volunteer it, I try to accommodate reasonable requests for early check in if possible.