I still use Windows XP in 2020 good ?

As long as you don't connect to the internet, your fine.
AVG Security will not help you.  XP is OLD, very OLD and no longer supported by Microsoft.  That means no more security updates.  Which leaves the system open to hackers.  AVG will not stop them.  Also, some new programs will not run on XP, Like the newer version of Microsoft Office or even Open Office.

No problem. We are a dying breed.