
Hem variations on young women, teens to twenty. Delineator, September 1925.
Generally, grown women (“Ladies’ sizes”) were illustrated with slightly longer hems in 1925, but the rules were not absolute.

Dresses for adult women/Ladies’ bust size 33 to 44 inches. Delineator, September 1925.

A row of Ladies’ dresses. (The women are chatting with men, one of whom wears a golf suit with knickers.)
Some hem variations are visible in that line-up.

Dresses for Ladies in larger sizes. Delineator, Sept. 1925.
No. 6268 & 6286 was available up to hip size 49.5 inches.

Not much larger than the usual Ladies’ sizes, but perhaps bigger than one would expect.

When it comes to unrealistic illustrations of large sizes, this is a star: would you believe size 52?
Well, it was also available in size 33. Nevertheless….
This color page featured Butterick dresses for teens and small women:

On a page of dresses for women age 15 to 20, hems vary. Some of these patterns were also available for small women. Delineator, Sept. 1925.
Notice the hem length difference between 6245 and the others. Although younger women (20 and under) might wear shorter skirts, there was some flexibility. (Besides, shorter women would need shorter skirts to remain in proportion.)
For schoolgirls (and younger girls,) the younger the girl, the shorter the skirt, with very young girls wearing dresses so short that they needed matching bloomers.

Left, an outfit suitable for schoolgirls aged 8 to 15. Right, this dress pattern for schoolgirls aged 6 to 10 came with bloomers for the youngest wearers.

Left, really young girls through age 6 might wear very short smocks with matching bloomers. Right, clothes for schoolgirls aged 8 to 15 are similar to women’s styles — but shorter. Delineator, Sept. 1925.

Styles for women; Delineator, Sept. 1925.
Some of those dresses came in larger sizes, often associated with older women. So when choosing a hem length in 1925, individual preferences might outweigh the dictates of fashion.
For a spectrum of styles:

Dress lengths for Teens (usually 15 to 20.) At or slightly below the knee.

Dress lengths for Ladies (usually bust 33 to 44 inches.) Definitely longer than the Teens’ dresses.

Dresses for women in large sizes. [‘Larger’ and ‘older’ were often equated.] Left, No. 6285 for women 36 to 52 inch bust; right, No. 6221 for women 36 to 48 bust. [Obviously illustrated as they might look on the smallest sizes given….]

Except for schoolgirls, women really did have a choice of lengths.
[Sorry about the picture quality — I took these many years ago.]