A few confusions about LOTBS?

Just finished ep 6. Gosh, I am in love with this show. That William Choi scene, looved it. Especially Lee Min Ho's dialogues and the way he delivered them. So funny.  Anyway, just wanted to clear up a few confusions-
1. Shim Cheong doesn't remember Joon Jae from the Joseon era? Why?
2. Did Shim Cheong time traveled to the modern world or did she manage to survive whatever managed to kill the other mermaids (with her being the last mermaid and all)
I know it's possible that these facts haven't been cleared yet, but I'm putting it here in case they have been cleared and I'm the one who missed them.

No you're right tattylovesofly, there were definitely other mermaids. They even waved her off a she went on her way to Seol.

It's still not 100 clear yet if they're both reincarnated or if she's older. I thought maybe her different color scales when she's a mermaid meant she was older or something. I think it's part of the slow reveal of what happened in the past.

she did not reincarnated, only JJ and his circle reincarnated..  JJ does not remember his past lfe

Well let's hope it gets cleared up soon

@Naksken That would be good too. As long as it does get cleared up in the end, and they don't leave us hanging :)

The add on, I vaguely remember in the earlier episodes saying the humans are killing off the mermaids (perhaps fishing them and killing them cause woohoo, a mermaid yay! and that indirectly not loving the mermaid kills them). I like to think she's the same mermaid but a little older.