Be wishy-woshy about mean, average (same thing), or median...It doesn't matter. It was not typical, or regular, or normative, or standard, or commonplace throughout 19th century society for young teenage girls to marry...
And, yet...it was quite commonplace, normative, standard, regular among the LDS society. JUST LIKE THE FLDS, TODAY.
I haven’t done much research, but the only historical records I can find easily deal with the era from 1890 on.
I’m not refuting your claim, just saying that so far I’ve seen people mention these historical documents, but I can’t find them anywhere I’m looking.