It would be almost 20 years of difference. While there are quite a few (much) older male, younger female couples (Roger x Rouge, Rayleigh x Shakky, Neptune x Otohime, Bege x Chiffon, etc.), there is not a single one (much) older female, younger male couple confirmed, as far as I know (Luffy x Hancock is the closest, but still not confirmed... and Streusen x Big Mom was more of grooming thing than a relationship.).