Would you choose the same ambition if you could not explain it to anyone?

An ambition that needs an audience may not be an ambition. Strip out the telling, the recognition, the imagined reaction of particular people, and see what remains. Some things survive that entirely, and some turn out to have been mostly about how they would sound, which is worth knowing before you spend a decade on them.

Try the test on something you are currently working toward. Imagine achieving it with nobody ever knowing. If most of the appeal drains out, the real want underneath is probably about respect or belonging, and going straight at that is more honest and usually faster.