When making a decision you have to do the best you can at the moment. The key is 'at the moment'. You must rely on yourself then. Not before and certainly not after. And that is hard. It is hard because you do not know what you do not know. You may know it later, but you don't know it now.
Trust your gut. heavily rely on your instincts. And then go with them. If it turns out badly, all is not lost unless you are a juror on a death penalty case. But even then there are appeals. Anyway, if your decision turns out less than idea learn what you need to learn and plan your exit strategy. Nothing lasts forever not even a bad decision and unfortunately not even a good decision.
Just do the best you can with what you have. Seek help when you need it. Give help when asked. Do all that and I believe the rest works itself out.