It is important to understand that not all individuals with disabilities will be eligible to open an ABLE account. The ABLE Act limits eligibility to individuals with significant disabilities with an age of onset of disability before turning 26 years of age. If you meet this age criteria and are also already receiving benefits under SSI and/or SSDI, you are automatically eligible to establish an ABLE account. If you are not a recipient of SSI and/or SSDI, but still meet the age of onset disability requirement, you could still be eligible to open an ABLE account if you meet Social Security’s definition and criteria regarding significant functional limitations and receive a letter of certification from a licensed physician. You need not be under the age of 26 to be eligible for an ABLE account. You could be over the age of 26, but must have had an age of onset before your 26th birthday.
more info here: http://ablenrc.org/week-2-who-eligible