Rosewood is a consripted (he actually enlisted but there's no enlistment policy in Rosice) full soldier by the country and would need proper armor, while women are only expected to support the army using voodoo magic and/or healing *if* they have ability. In this case, Ria hasn't been supplied armor because she surprised everyone when she volunteered to fight despite no ability. Instead, she is having to wear basically the same clothes she wore when she came to the village. I wouldn't expect her to get any equipment support, soldiers need to supply their own equipment in this world.
FYI you'll also find that women in this world have a very unequal (lower) standing compared to what we would come to theoretically expect in the current modern world.