Keep using the version of SketchUp Make you have now. No need to change anything. Someday the operating system may make it obsolete but based on past experiences, that won’t be for many years. There are still many users using ancient Google versions of SketchUp with no problem.
You can migrate to SketchUp Web. It’ll open your old models just fine.
Switch to SketchUp Pro. This will keep you up to date with the desktop client version. Of course this is the option if you are using SketchUp for commercial work but then you should have been using Pro all along.
Assuming you are just a hobbyist using SketchUp, likely your best option will be number 1 for the time being. Actually you might do a hybrid of options 1 and 2 so that you get familiar with SketchUp Web. Besides there are some benefits to using it over Make and you might want to leverage them.