I'm sat in a Denny's somewhere in AZ, but...
Use a combination of Datedif (or Datediff - one is for VBA) and Today(), with their DOB.
For the DOB though you'll have to spoof the year portion - so =DATE(2024, MID(A1, 4,2), LEFT(A1,2)
Basically something like
=DATEDIF(DATE(2024, MID(A1, 4, 2, LEFT(A1, 2)), TODAY(), "d")
Depends on the format of the date of course.
You can then use this in conditional formatting
Probably 🧐
Edit - or filters 🤓