Google search for website has wrong date

Initially we set up our website with a date of Oct 3. Since then it has been changed to Oct 26. I have updated it everywhere I can find on the website but when I had my sister google search and look at the website as a test, it shows as Oct 3 still on the search. Once you click on it, everything within the website has the correct date. Any insight on where I need to update to fix this issue? I don't want to cause any confusion with guests. I did go in and mark the website as private and protected with a password after I initially created it, maybe that is what's causing the issue? Thanks for any help!