Hi Neale,
It is interesting how we all make theories based on different things.
Don't laugh, but I have concluded the 2 girls age by looking at the "other" girl's teeth by enlarging and scrutinising the resulting blurry image of her mouth .!!
To me I see the dentitiion of a child aged 6 to 7 years.
Because they are about the same height, I then conclude same age.
I would gladly own up that it is not strong logic

Sue
Adding, Looking at the seond picture, I see a girl in school tunic, but this may well be simply a dress in the pinafore style.