(a) Commencement. A program of education or special restorative training may not be afforded prior to the eligible person's 18th birthday or the completion of secondary schooling, whichever is earlier, unless it is determined through counseling that the best interests of the eligible person will be served by entering training at an earlier date and the eligible person has passed:

(b) Secondary schooling. Completion of secondary schooling means completion of a curriculum offered by a public or private school which satisfies the requirements for a high school diploma or its equivalent - usually completion of the 12th grade in the public school system.

(c) Age limitation for commencement. No person is eligible for educational assistance who reached his or her 26th birthday on or before the effective date of a finding of permanent total service-connected disability, or on or before the date the veteran's death occurred, or on or before the 91st day of listing by the Secretary concerned of the member of the Armed Forces on whose service eligibility is claimed as being in one of the missing status categories of § 21.3021 (a)(1)(iv) and (3)(ii).

(d) Termination of eligibility. No person is eligible for educational assistance beyond his or her 31st birthday, except as provided under § 21.3041(g)(2). In no event may educational assistance be provided after the period of entitlement has been exhausted. In an exceptional case special restorative training may be provided in excess of 45 months. See § 21.3300.