Quality Miles Monday - I can't pace myself

Plan: Same as this day, 54321 workout.
Actual Mileage: 4.7 miles today, including lots of walking.
Route: Around the marsh in my neighborhood.  "The marsh" is 0.6 miles so I've been running as many loops around it as I want for various workouts.  It's basically flat but not a total pancake.

Weather: 70s and sunny.  It was glorious.
Execution: So, I felt strong, and going fast but not out of my mind.  But I did not hit the prescribed paces.  I am having significant difficulty pacing off my Garmin watch.  It kind of makes me insane.
Planned 5:00 at 10:30 pace. Actual: 10:27/mile (Good!)
Planned 4:00 at 10:00 pace. Actual: 10:19/mile (Ok, that's not so bad.)
Planned 3:00 at 10:00 pace.  Actual 10:32/mile.  (Doh.)
Planned 2:00 at 9:45 pace. Actual 9:27/mile.  (Good job!)
Planned 1:00 at 9:45 pace.  Actual 10:17/mile.  (Ooof.)
From today, I learned: I wrote my coach and asked if I should be doing more of these runs on the treadmill to learn what the paces feel like. We'll see what she says.

Bonus: I did my new "leg day" routine this evening as well.