I had a hard time finding it as well. I think maybe because the text is underlined and the font is small? It is harder to read "into" that text. Maybe it should be on its own line? Or it should be up next to "Full Color" / the cover? Maybe some "copy" pro would know the reason right away but it seems rather hard to find to me.

While I agree that it could be more prominent, the old man in me wants to scream "Don't be so lazy in reading!"

If you ignore the reviews near the end, the page doesn't have a lot of text. And not everything needs to be accessible by quickly scanning.

I found the age guidance with cmd+F, "age", enter. Probably would have tried "year" next if that hadn't found it.