I use Windows xp in 2019 what risk?

From experience, no risk. Just make sure your anti-virus is always up-to-date.

The major problem you'll encounter is that as the days pass by, more and more websites refuse to show content if they detect that your OS and/or your browser is that old. Let's face it, you can't update your browser anymore. XP is still great for other tasks but not so with the internet.

No current version of any web browser supports Windows XP. That means whatever security vulnerabilities exist in that old version are a risk.

As an example, the last version of Firefox to support Windows XP was 52.9.0. Any security vulnerabilities fixed in subsequent versions should be considered to be present in Windows XP, unless it is in a feature that 52.9.0 doesn't implement.

https://www.mozilla.org/en-US/security/known-vulnerabilities/firefox-esr/

 

I use it, but you find many sites today require newer versions of browsers, means newer OS.
Still a good bench machine though offline.