Upstairs, downstairs

We have seventeen stairs in our house. Seventeen stairs separate the first floor from our second floor. Since we had no stairs at all in our old house, I worried for weeks about William and these stairs.

Well, earlier today, William learned to climb them. Apparently, once he figured them out, he figured them out. Tonight, before bedtime, he climbed the entire seventeen stairs at once, with one very very slight hesitation on the landing. That's seventeen stairs. Seventeen stairs at once. It's a loooong way up, but William "No Fear" Wyckoff wasn't deterred!