Got it, yeah that workout makes no sense and I would drop that coach immediately.
I saw on another thread that you're targeting indoor masters in March? Is that still your plan? If so, whatever speed work you do now isn't all that important, but it's pretty clear that since you've refrained from speed since June and are a bit overweight, goal 3K pace isn't going to make sense now unless it's for short bursts.
Why not just do light speed work to get the legs moving, e.g. 10-12 * 45 seconds or so?
By the way, I'm in my late 40's and making a comeback in the mile/3K after a 15 year layoff. I don't try to run certain goal paces in training, I run exclusively off of perceived effort (e.g. mile pace, 3K pace, 5K pace) and it's working really well.