Would you advise someone at 40 yrs old to pursue an engineering degree?

Why not?!  I consider myself to be a forever-student, trying to learn something new everyday.  There are always new discoveries happening in science and technology, there is always a need for the next new big thing, and the way that those ideas come alive are from fresh new minds.  That doesn't mean that it has to be a young person just starting off their educational journey.  It can come from someone who has been on the journey for a while and maybe decided to take it in a different direction.  We all need perspective, new ones, different ones.  Your experience will give you content that younger folks might not have.  Use your gifts, talents, and skills to move you forward in the direction you want, whether it's engineering, art, etc. to get to your happy place.  Basically, do what makes you happy and you won't regret a thing.