We all have the recurring nightmare of sitting in a college exam with two empty blue books and a sheet of essay questions. You are given the option of answering three out of five, but you go down the sheet and can't answer one. You have nothing to write and three hours to not write it.
Then you wake up in a panic. If in possession of a college diploma, you will look for it in the dead of night. If found, it will provide about 10 minutes of reassurance. There are only two ways to stop the panic, and psychotherapy is more expensive and less fun than going back to school. At the very least, being a student again will supply new fodder for anxiety dreams to replace the ones that are 30 or 40 or 50 years old.
No matter how "too old for school" you think you are, you are not as "too old" as Hazel Soares of San Leandro. At age 93, Soares is entering her junior year (or years) at Mills College in Oakland. An art history major, she's taking it nice and slow - slow enough to walk across the stage and accept her diploma at age 100.