Can't find the poem I'm looking for, which is about to be published in Coffee Pot apparently (details to follow) but I'd better rescue this while it's here.
lioness
39

At the age of thirty-nine
I'm getting past my prime*
Elusive gravitas
As the years pass
Most go
For the big four oh-
for me it must suffice
To have been thirteen thrice

n.b next prime at 41