I know that sounds a little bit stupid but: In a way going faster makes things easier. I recently improved my 5k record by a couple minutes (sub 22) and when I compare it to me 2 years ago it is in a way easier, because I only need to run at my peak speed for less time.
I am sure with time you will have a similair experience.
But in general if the ending is hard and the beginning easy then you should start/run at a slower pace at least a couple times on this distance.
I know that sounds a little bit stupid but: In a way going faster makes things easier. I recently improved my 5k record by a couple minutes (sub 22) and when I compare it to me 2 years ago it is in a way easier, because I only need to run at my peak speed for less time. I am sure with time you will have a similair experience.
But in general if the ending is hard and the beginning easy then you should start/run at a slower pace at least a couple times on this distance.
I often struggle with pacing in general, park run here is like 600 or so people so I usually keep with others for a while.