You have good words for it.
Decisive. You are not someone who dithers. Realistic. You see things clearly and you do not kid yourself. Knowing your own mind. Trusting your gut. Not overthinking it.
Every one of those is a flattering name for the same move: you could not tolerate the open question, so you forced it shut, and then you dressed the forcing up as a virtue.
Here is the tell. A genuinely decisive person can also wait. They close the question when it is ready to close and they leave it open when it is not, and both feel fine to them. What you are describing is not that. What you are describing is a person who cannot leave anything open, who has to resolve, who calls the inability to sit in a question "knowing myself."
The honest name for it is not decisive. It is that the gap is unbearable, and you have spent years building a vocabulary that makes fleeing the gap sound like character.
The disguise is good. It fooled you, which is the only audience that mattered.
one thing: take the quality you are proudest of in how you decide. Decisive, realistic, whatever it is. Ask once whether it is the strength you think it is, or the flattering name for not being able to stand not knowing.
Josh