Wunder Train sizing?

I was hoping to get some Wunder Train leggings and bra during the Boxing Day sale, but I’m conflicted about what size to get since some people recommend a size up in Wunder Train.

I am 4’11’’ and around 125 pounds. I have a size 4 in Align leggings. If this helps, I take a size 27 in Abercrombie jeans.

Based on the size chart, it looks like I would be a size six, but I thought I’d seek out other opinions!