Last Shabbat I slept through the time to say Mincha. I had a few guests over and I went to take a nap after serving and well... After Havdala I realized what I had done so I said Maariv instead but I was left wondering if I had done the right thing. You see it is not my custom (or any women in my family) to say Maariv. So was it right for me to say Maariv instead of Mincha?

It says in "Ishei Yisrael" that a woman can daven the next Tefila twice as a compensation for the Tefila she missed, if she usually davens that second Tefila (in your case Maariv). If not, she is not obliged to daven the next Tefila twice to compensate. It can be a good idea to do Hatarat Nedarim so that if she forgets a Tefila or can't daven for some reason she wouldn't need to compensate for it. Rabbi Ro'i Margalit