This morning, Amy wanted to type her name again, so I fired up MS Word, the way I usually do, selected a big font size, and hit Caps Lock (since she's more familiar with capital letters).
After she was finished with that, she spotted the punctuation keys at the bottom right and asked whether she might press them. I said yes.
She pressed , a few times first, and then wanted to make a ; by pressing on the top part of the key, which didn't work, of course. So I showed her the left Shift key and told her to press and hold that and then press the other key, and she made some semi-colons.
Then I showed her how she could use the right Shift key to make a capital A when Caps Lock was off, and she played around a little with upper-case and lower-case letters.
I can see that she still has to practise a bit, since she had a hard time releasing the letter key before it autorepeated. Though since she mastered that fairly quickly before, I think she'll get the hang of doing so while the other hand stays on the Shift key, too.