I did some research on her background and found this profile page:
https://www.fura-fura.net/好評配信中/月花さん/
According to the profile, she was born on December 21 and is originally from Fukuoka Prefecture, Japan. She was scouted in Hakata and became an SM dominatrix. She retired from professional dominatrix work in 1998.
Her exact age has never been made public, but based on her career timeline, I would guess she is now somewhere in her mid-50s to around 60 years old.
The profile also says that she later ran a bar in Shibuya, although it may have already closed.
Interestingly, this page originally included two MP3 interview recordings, but they are no longer available.
It appears that she still occasionally appears as a guest at events held at a bar in Kabukicho, Shinjuku. One of their announcements says:
"Guest: Mistress Tsukika (月花女王様) on the first or third Wednesday of every month."
Her X (Twitter) account:
https://x.com/2k1ka
Her official website (archived):
https://web.archive.org/web/20231102145133/http://www.tsukika.org/
Also, it appears that around 2012 she was running a reptile-themed bar in Shinjuku. However, both the bar's website and blog have been inactive for many years, so I assume it has probably closed.
https://nikkan-spa.jp/143423
https://bar13th.ikidane.com/top.html