We don't have stairs in our apartment. But J had no problem figuring out how to climb them any chance he got! Going down is a different story. We don't have many opportunities to teach him how, and now he wants to go down the stairs the same way as us, not backwards.
He is 16 months. He would definitely fall face first if I let him go down without holding my hand.
When did your toddler learn to navigate stairs?