If the DL
seat map on your flight matches this seatguru one, pick another seat. DL
has a bunch of different configurations in the 757 fleet and some have missing or misaligned windows around rows 21-24 so select carefully. You can also refer to website "seatexpert.com" who has a reasonably accurate layout of the various 757's as well. DL
itself does not advise of missing/misaligned windows on its aircraft seat maps shown on delta.com so in most cases these 2 websites are pretty accurate.
Not fun to be expecting a window and end up with a blank sidewall panel. Nice to lean against to nap, but no view!
P.S. I recently rode an AS
734 and the passenger seated in row 9 asked the F/A to be reseated because they were a fearful flyer and had to at least look outside for a point of reference if it got bumpy and fussed that no one had advised them their row did not have a window.
watch what you want. you may get it.