If Northwest Metal, then use nwa.com to select seats, what Delta shows will most likely be incorrect as you are currently seeing on your reservation. If it it Delta metal, then either website will show the correct seats, but you should still select them on Delta.com.

As for your exit row problem, wait until 24 hours before your AZO-DTW flight and you will be able to select them at no charge, otherwise, 5A, 5C, 5D, or 5F on the A319/A320 aircraft are just as good if not better seats than the exit rows anyways.