Steve Krouse, in Lunch with Alan Kay: how to become educated enough to invent the future:

Alan also said at lunch that one problem young people make is “having goals.” It’s too early to have goals that “consume one’s horizons,” because young people don’t even know what they don’t know. I think this kind of epistemic modesty is a great idea. I can probably benefit from shifting the focus from my overly-specific goals to “more meta” goals, such as becoming “educated” in a broader sense than I previously thought was possible. The more perspectives I can acquire, the better I’ll be at not fooling myself, and the more I’ll be able to appreciate the richness of the world.

I've had an extraordinarily-difficult time forgiving myself for not achieving certain goals I set in my late teens. And without being condescending at all to those younger than I am now, or to myself back then, I finally agree with this: a goal is just an idea you had. It might be a good one, it might be terrible, it might lead somewhere interesting, it might ruin your life. Following your feelings and interests is good, but committing early to something that "consumes your horizons" is... not a great idea.

There's a lot of pressure on us to specialize, to start a career, to become something, anything as early as possible. I beat myself up for a decade because I didn't become a professional musician by age 20, but my god; the chances of that happening given where and who I really was were so slim. It wasn't my fault that my life took other — difficult but often quite interesting and fulfilling — turns. The only real effect of refusing to give up that ghost dream was that making music drained of its pleasure for a long, long time. What a shame that is. But it's okay. I forgive myself my passion, because it came from a beautiful place but was wrung out by horrid cultural forces.