Get over the idea that only children should spend their time in study. Be a student so long as you still have something to learn, and this will mean all your life. ~Henry L. Doherty
My net research says the oldest university student is 95 year old Nola Ochs from Fort Hays State Universtiy in 2007. Mom is not actually the oldest student and in fact she is more than 3 decades younger than the oldest student on record hence she has a lot of educational mileage on her odometer.
She's taking up an associate degree in Early Childhood education at a state college in the US. This comes 3 decades after she finished her Masters in Public Administration in her hometown university when we were growing up.
To up the ante, she's doing this while working at a pre-school. This actually qualifies her to be called A WORKING STUDENT.