Welcome to the Uphill Athlete forum.
But this is a good thing, right? My aerobic capacity and ADS is AWFUL. But this means after some retraining, there is a lot of room for improvement to gain speed and endurance, right?
To get a better estimate of your Aerobic Threshold (AeT), I would recommend doing a heart rate drift test. Check out this article that has some good information on different ways to assess AeT and the pros/cons of each approach.
Wish you the best with your training.