Moms have changed in the past few generations. I don't mean the way they act or fuss or worry or care, but the way they look, at least in the popular culture.
Consider an ad from 1947 for, let's say, Wheatabix Grain Bricks. The mom in the ad would be in her late 20s or early 30s, beaming, setting down a plate in front of wide-eyed kids who had exclamation points coming out of their heads. Mom's wearing a frilly apron and shoes with clunky heels, as was the style. She's energetic and engaged, and she's happy because Grain Bricks sent Johnny and Mary off to school filled to their eyeballs with riboflavin.
The same magazine with this happy tableau might have an ad aimed at older moms, who had graduated to "Mother." She had crossed the temporal equator of 50, whereupon some gremlin walked up behind her and smacked her with the matron stick, hard.
Her hair, once fire-hydrant red, went instantly gray and was rolled into a tight bun that sat atop her head like a teakettle lid handle. She assumed the shape of the Pillsbury Doughboy, put on a black smock with a bit of lace around the neck, and then, because she found herself in an ad for Western Electric, she sat down by the phone to wait for Johnny to call. (He didn't, but that's fine, he's busy.)
There was no in-between for moms and mothers. It must have made for some interesting 50th birthday parties. The transformation might happen in the middle of blowing out the candles.
This paradigm had faded by the time I grew up. It was transplanted to grandmothers. But even that's different now: ads are more likely to show Grandmother skydiving or riding a Harley.
There's one thing that hasn't changed, though. The card. You have to send the card. You'd better send the card.
In my grade school, we made a card. We'd assign properties to the letters in MOTHER and make a poem out of it.