Wow. That looks eactly like her.
About the ring: It's a bit of a long shot, but a lot of people propose with rings that were passed down through the family. It could be that she was dating C.B, and he proposed using the ring that was originally given to his mother or grandmother. The inscription of 9.4.1920 could be the day the (presumably grandmother) got engaged or married, and was the original inscription. Then the "C.B to E.J" inscription came much later when C.B proposed.
About the ring: It's a bit of a long shot, but a lot of people propose with rings that were passed down through the family. It could be that she was dating C.B, and he proposed using the ring that was originally given to his mother or grandmother. The inscription of 9.4.1920 could be the day the (presumably grandmother) got engaged or married, and was the original inscription. Then the "C.B to E.J" inscription came much later when C.B proposed.