Bricklaying is not a job for the inexperienced do-it-yourselfer. Construction of a mortar-required brick wall is a challenging undertaking. No one without experience as a bricklayer should attempt to construct a brick wall taller than 4 feet (1.2 meters).
For an intermediate apprenticeship, you typically need some GCSEs, including English and Maths, or equivalent.
Interestingly, the general public commonly uses "mason" and "bricklayer" interchangeably.
Individuals of various ages have demonstrated the viability of reentering the workforce after an extended break. Learning a new skill or retraining is always an option. This is also true for the profession of a bricklayer.