i got this message after the update should i downlwed it

I dismiss it because it basically is like system restore. Or make regular backups of your pc using backup software and you don't even need that.

If you click remind me later the next time you open support assist after a shutdown or restart of your pc you will see this again.

If you click dismiss you won't see it until SA updates again.

And lets go means it will install OS repair for SA. 

You can still keep the plugin for it in programs if you don't allow it, but you need the plug in if you decide to use it.