Celtic women certainly enjoyed better rights than their greco-roman counterparts. The problem here is that we are missing so much data about the pre-roman celtic societies, what the romans wrote about them was that they held a traditionally subservient role, but they almost certainly held authority in religious duty, as regents or as advisors. We also have legendary examples of ruling celtic women (I think everyone knows about Boudicca). The definitive answer though? Impossible to tell.
To me personally, the genders are just portrait flavor, no reason to fret over something that is most likely a complete breeze to mod, if that honestly bothers you.