Woah, I don't think they will go for a decade gap between Storm and T'Challa, but it is true that T'Challa older than Ororo in the Intergalactic Empire, she was matured as well, so I saw them more like they have several years difference in that story arc. Like Storm is around 35-36, while he is like you said 38-39.
But for the one in KiB BP, yeah they look like they have 5-10 years difference now... just now noticed.