The former world champion - she won team and mixed gold for China in 1983 - would be the oldest table tennis player to compete in an Olympic Games by the time the tournament is due to open on July 24.
Originally from Shanghai, Ni was scooped up by Luxembourg some 30 years ago - initially as a coach.
Table Tennis
Emotional Bayley treading fine Paralympic line after battling through to Tokyo 2020 final
28/08/2021 AT 10:49
She has since competed in the 2000, 2008, 2012 and 2016 Olympics, achieving her best result when, aged 37, she reached the last 16 in Sydney. She hopes Tokyo 2020 will go ahead.
"Unfortunately the situation is like this; nobody knows what can go on, what can happen," Ni told Reuters at her training centre in Luxembourg, adding she hoped the Games would be postponed in the worst-case scenario, but not cancelled.
"If we can do the Olympics, I think it's good for everybody," she said.
Japan's government and Tokyo have said they are still committed to the Games beginning on schedule, and the International Olympic Committee has repeatedly swatted aside any suggestions of a postponement despite multiple sports events around the world being cancelled amid the epidemic.
She knows this Games could be her last, although she has not completely ruled out a shot at Paris 2024.
No other athlete has competed in a table tennis tournament at the Games at her age, the International Olympic Committee's official media outlet said.
Ni limits her training to around three hours a day, often sparring with her husband and coach, and focusing on physiotherapy to speed up recovery and limit injuries.
Luckily, I have a good physiotherapist and that helps me a lot," she said. "I really need it. We cannot (go) against age, cannot (go) against nature, and so without this ... care, I think it's very difficult to continue.
Tokyo 2020
Tokyo 2020 - China vs Germany - Table Tennis Men's Team Gold Medal - Olympic Highlights
06/08/2021 AT 13:46
Tokyo 2020
Tokyo 2020 - Japan vs Republic of Korea - Table Tennis Men's Team - Olympic Highlights
06/08/2021 AT 05:50