The answer is there is no answer.
Run your best, whatever your best is. Every runner or former runner has a story. Make your own. Live with whatever your talents were or weren't and whatever your peak was or wasn't.
My very first week of XC practice way back in 1992 I ran 40 miles. I had run 1-2mi 2-3x a week for a couple weeks before that.
I had a surgery after XC season then quickly got up to 50-60mina week before track.
The summer after frosh XC I was running 70mi a week. Prior Jr XC I was running 80mi a week. This is all probably vaguely accurate. I increased mileage initially with doubles. 7/3s or 10/3s. 10 miles a day and 14mi long run was my norm for a long time. 3mi shake outs were sprinkled in.
I drank myself out of any decent collegiate running. A washed up has been who then got a marathon itch. Eventually got up to averaging 100mi a week for an entire year with sustained peeks of 120-140.
I was always big for a runner and never got under 140lbs at 5'6". Results are what they are: 4:27, 9:32, 15:43, 32:08, 1:09:40, 2:32:45. My best race I felt was a 48:56 15k back in 2000.
Alan