Edit cell based on year entered

Good morning ladies and gentlemen!

I recently created an inspection report which contains various 'Year service is due' fields. When I enter a past or present year, I'd like the cell background to turn red. If I enter a future year, I'd like the cell background to stay white. I don't know how to write code but I assume I can create a java script in this case. Can someone please assist?

Thank you in advance!