Here's another pic.

Last time I sat in 13A, I could swear that the seat was narrower than other seats on account of some protrusion by the exit door. I didn't pack a tape measure to verify, but I felt pretty confident in that assessment. That, along with the tray tables in armrests, are good to know if you are claustrophobic.

You may wish to keep an eye out for a seat in row 10 as upgrades to First clear, as I prefer 10 over 13.