"Juvenile" growth in freshwater pearls

[Mostawesomecoffee]

I read that "juvinile" growth produces superior nacre to "non-juvinile" growth. I've heard of "juvinile" growth defined as either growth of a young mussel, OR the growth of an older mussel after coming out of a period of winter dormancy. Assuming my understanding of "juvinile" growth is correct, does this mean that it's possible to have a very old mussel produce very fine nacre after it comes out of dormancy? Is there an age/size limit beyond which older mussels won't produce fine nacre? thanks.