Advice . . .

for my grandchildren to whom I have given journals

There's nothing new under the sun
It's all been thought and said and done.
But when, my friend, it happens to you,
Everything's fresh, everything's new.

Which means you ought to write it.
Put it in a journal. Try an essay (Essay: an attempt; a trial, meaning try). Don't stop to evaluate the the idea or experience. Write it first, then you can evaluate.