Many people think that they will fail just because they can’t see success now.
Just like a student, flipping over her book for the first time, she will not understand the theory and formulas in it.
It will take time. It will take guidance. It will take repetition. And it will take several attempts from different angle. And eventually, slowly but surely, her understanding will become stronger and possibly even become an expert on the subject.
Can’t see your success? Similar, all you need to do is what the student did. Repeat. Practice. Experiment. If you can do that, success will be just a matter of time.