It was simply not proper for young girls and young women to wear makeup. This was something actresses (who did not enjoy the status they do today) and fast women did. Later on in life, perhaps in your 30's or so, skillfully applied cosmetics were acceptable, but one could not look obviously made up. For those who think this old fashioned, when I was a young woman in the 1970's, many of us had similar views. I never wore anything more than mascara and a bit of lipstick until I was in my early 20's - except for formal portraits. My own daughters were wearing lip gloss by the age of 10!