My cohort isn't "average" then. We had 2 couples (I'm half of one of them and I am over 40. My husband is 50+), we had 8 women 50+ and two of them were african american. We also have asian americans, african americans, and other ethnicities of more "traditional" age represented. As a group, we are diminished now. We began as 44 PCTs, we're down to, I think, 22.
If you're a white volunteer in rural South Africa, as I am, you will be the "racial" minority in your village. Ditto if you're Hispanic or Asian, or etc. In fact, though, in whatever way you do or don't look different from the people in your village, you will the minority in terms of your cultural views and sensibilities. We are all Americans serving, and the cultural divide can be quite wide at times.
That said, we are the first white people many of our learners and the villagers had ever spoken too. We don't get harassed too much, because we're older and married, but I still hate being called umlungu. Gender roles: There are some rather fixed gender roles here, but I see young people challenging them. If your experience is at all like ours, you'll find that as an outsider, you're going to be strange in so many ways that people won't be too concerned about you flouting gender roles. My husband openly helps with the laundry and no one bats an eye. For the stress, try as many different strategies as you can for cultivating patience. Things can be frustratingly slow or never happen at all. I'd get really upset at the inertia, but after almost two years, I am *finally* learning just a *bit* of patience and have fractionally improved at letting some things go.