Ae only thinks in pixels; if you’re using it for print, you have to do the math yourself.
Assuming this is 11in x 17in, and assuming a quarter inch of bleed all around, and assuming 300 dpi, that works out like this:
11.5in * 300dpi x 17.5in * 300dpi = 3450px x 5250px
(Of course, you’ll need to confirm units, bleed and print resolution to calculate the final pixel dimensions correctly.)