What Is the Oldest Age You Can Be in High School?

The oldest age a student could be enrolled in a high school program was 20 prior to 2009. Following the 21st birthday, the person was considered no longer eligible. A new statute was passed in 2008 that raised the age to 25.

The applicable age for a person with intellectual and developmental disabilities to be enrolled in a high school program is 21. The age being raised to 25 caused concern; therefore, each independent school district has the right to refuse educational services to persons over the age of 18. General education development, or GED, programs are available to adults who wish to earn a high school diploma.