The decision is probably going to be out of your hands. The worldwide situation is extremely fluid at the moment with countries suddenly imposing entry bans and restricting internal movement, airlines suspending flights, etc. And of course, despite Olympic officials swearing blind that the games are going ahead, there's a possibility that they will be delayed or cancelled (I think it's highly unlikely that they'll be going ahead as scheduled).
My mother (from the UK) was due to visit me in Japan next month and it looks all but certain that she won't be coming. For a start, she has to change planes in Denmark, which has just announced a ban on non-residents entering the country. She has had the philosophical view that what will be will be, though she's disappointed of course; it may be best for you to have a similar view.
If you do get a choice, bear in mind the usual things - your age and state of health, as well as the people you spend time with, the prevalence of coronavirus in your country and in Japan, etc.
[Other mods - I think the previous post would be best as a new thread but am not sure how to move posts. Could someone do this and tell me how to do it]
@tennisbeverly, do you already have tickets for your events? Have you already purchased your flight and accommodations?
Do you know the refund policies for these things? Do they have exceptions for these kind of circumstances, or do you have travel insurance that can help you recoup the sunk cost?
There's a lot changing and there's no telling what kind of official decisions will be made, but I don't expect it'll be resolved in time for the Olympics to go on as planned; the incubation period alone means this is going to be on the radar, probably disrupting all sorts of plans and events for the rest of the year and possibly beyond. Like Lothor said, you may not have much choice in the matter. As they say, hope for the best, but plan for the worst.