We can never be 100% sure a decision is going to be right, no matter how much information or experience we have. As the old saying goes, "life is risky". It's all risky.
I find it more helpful to think, "This is the best decision I can make right now" knowing that inevitably it will sometimes be the wrong decision - and accepting that. A wrong decision may sometimes bring some regrets but that's part of life. It's still way better than the alternative - paralysis by analysis.
Taking time to reflect is good if it
leads you to better decisions.