Sell the Legacy TNISA to fill up the New NISA?

[Bubblegun]

Previously we had to stop because they became adults at 18, but couldn't contribute further to the NISA because they weren't 20.
So we can restart putting money into the NISA when they are 18/19?

At 18th birthday they get a new password forced on them (at least by Rakuten).
This year at least my offspring had an existing J-NISA when turning 18 so the first year they can start 'adult' NISA will be 2024.
In the future I guess this will not be an issue as there will be no more J NISAs.

That’s interesting because my kids haven’t been forced to get a new password. Unless it’s slipped my mind.
So they can still contribute at 19. As an adult. That’s good news for them.