Learning to use money is a skill. Like every skill, it takes time and conscious effort to really understand and develop.
Dr Mike Murdock said " if you don't have any regrets, you've not learned anything ".
So in your learning process, you're bound to make some mistakes.
I have learned not to assume, I've learned not to be hasty, I've learned to do my homework and am still learning. However, above all, when I fall, I've learned to forgive myself.
I have met people who have given up. " Business is not for me" they say. It was their fear speaking. Their inability to forgive themselves had caused apathy and fear. The irony is that the one who tried and failed is way ahead of the one who hasn't.
Forgive yourself. Cut yourself some slack. Learn to laugh at yourself. Let your failure help you develop empathy for others.
"....And don't take yourself too seriously-- take God seriously." (Micah 6:8 MSG)