Capricorn dilemma

I am a Capricorn from former Yugoslavia who achieved a degree in pure math and mechanical engineering in my twenties, I am in my forties teaching difficult secondary school kids - I get the impression that I wasted time learning something which has no bearing on life skills, and fruitless when I think of the endless possibilities that could and should have presented itself to me, all these years for nothing, putting up with tight schedules, unappreciative staff and derogatory and offensive school masters - I can't even expect much from them because they don't give a damn about quality or integrity, they only care about keeping up with the current zeitgeist.

I find myself having to lead by example all these kids what to do in life and how to do it, I give advice, but however much I do so I always reflect on what had happened to me and the current situation I am in. Can I, should I encourage my students to follow a path similar to mine through higher education and hard work, or should I just tell them to be responsible individuals and do what they think is best for them, whatever that is?