In my younger days, I would run a mile for each year of life to celebrate my birthday. Since I am neither a marathoner nor an ultra-marathoner, I have adjusted my target this year to be a tenth of a mile for each year, hence 5.4 miles.
This was a doable goal. With my recovery, the longest I have gone thus far was three but I felt it would be ok without pushing it too much to go 5.4. It was fine. I had a really good run. An easy pace: running between 9 and 9:30 per mile. It was cold, 18 degrees F with little wind.
Next year, avoiding injury, I should be able to go a minute for each year.
On your birthday, do something special. Choose a mile, tenth of mile, or minute per year to celebrate and mark your birthday.