This outfit is so cute and it can be worn any time of the year. We've worn the top with other pants, and the pants with other tops. It does run big, so I'd recommend sizing down.
This ruffle pant set is even more precious on! The smocking is high quality and the fit is true to size. The pants were just slightly big on my two and a half year old but nothing that one roll up in length wouldn’t fix. I would stick with your true size. It is an adorable outfit!