Trying new things can be a very terrifying experience for almost everyone. However, if your immediate thought when presented with a new opportunity is "I don't think I'd be able to do that. I'm just not ____ enough" (you fill in the blank), then there is something about your way of thinking that you must try to change. Perhaps you grew up feeling inadequate in certain areas, and did not receive the greatest results when you tried something new in the past. It is perfectly normal to have certain doubts in life, but the problem only occurs when you doubt yourself SO much that you don’t even try.
You can talk yourself out of so many amazing opportunities simply because you do not give yourself a chance. Whether it is to apply for a new job, school, or moving to an unfamiliar place etc. YOU must know and believe that you are capable. When you are not confident in yourself, it can reflect in almost everything that you do. Also, it will make it very easy for others to take advantage of you.
So you may not have a single clue how something will turn out, but if it is something that you are passionate about, or you know can better you in the long run, take the first step. If you continuously procrastinate and put things off out of fear of failing, you will remain stuck in the same position for a very long time. Mistakes are inevitable, and can happen to even the most cautious person. Making a mistake is proof that you have tried something new and that you are growing. Be your own #1 fan, and quiet that doubtful voice in your mind. You will be surprised by how much you are truly capable of!