When did Pindar start writing poems?

There's no definitive answer to when Pindar *started* writing poems. We don't have any surviving early works from him.

Here's what we do know:

* He was born around 518 BCE.

* His poems are all victory odes. These were commissioned to celebrate winners of athletic competitions, specifically the Panhellenic Games (Olympic, Pythian, Nemean, and Isthmian).

* His earliest known poems were written for the 470s BCE.

So, while we don't know when he first started writing, we can say he was definitely writing by the 470s BCE.