You can buy previous event items from a Calamity Salvager. Though I'm not sure if the Peach Blossom Earrings are available there. I think they might be...

However, They're not new this past year. They've been in the game since 1.0. This previous Little Lady's Day was actually not the first Lady's Day in the game. This is the second time those earrings have appeared, and were actually the main event item for the holiday in 1.0. You probably didn't know they were in it because it was something you could buy from the previous year...

Therefore, rest assured that they'll be back next year.

But in the meantime, check with a Calamity Salvager..they might have them for sale.