3a. If there are less than 15 women then it means that whatever metric you used to pick "best" may have an unconscious or unexamined bias. Now you have to decide which do you consider more important, sticking with your "best" metric or trying to find and eliminate that bias?

4a. If sticking with your "best" metric is more important, then you are now deliberately excluding female candidates for reasons that are fundamentally unfair to them.