There's an M on the back of my cameo?

by Michelle Janicki
(Lockhart, Texas. )

The M is on the top right of the second picture.

There's an M on the back of my cameo. What does that mean? The woman who sold it to me said it means it's probably from Italy. Is that true? Also could you tell me if it's old or not. And if so how old. Thank you.