I think it would be better for discussions of decision-making in general, and decision-making by young people in particular, if we reframed decision-making from "avoiding regret" to emphasizing that: -It's okay to change your mind at any point, and -Your feelings at the latest/most recent part of your life are not more important than your feelings at any previous part of your life.
If someone says "You'll regret that in 20 years!" -- first of all, they don't have any possible way to know that, but secondly, what they're really saying is "I expect you to get 20 years of happiness out of that decision." 20 years of happiness is nothing to sneeze at. If you get married and 10 years later, you decide you don't want to be married anymore, and you get divorced, then, okay. You get to make that choice, and you got to be happily married for 10 years.
This whole cultural attitude is based on the assumption, not only that changing your mind is impossible or shameful, but that your life is a linear process of working your way towards a True Final Form, and that if you undergo any changes between [past age] and [final age], that means your [past age] self was not your True Final Form and should have been considered too young to make decisions. It's the underlying premise that at some point in your lifetime, your self-identity (sometimes synechdoche'd as "the brain") stops changing (spoiler: it doesn't), and then and only then are you your True Self; then and only then should you truly be allowed to make your own decisions, because your selfhood is fixed and your decisions will be free of regret.
It doesn't work like that. The self is constantly changing. Just go with it.
