It is not uncommon to be worried about failure when starting a new business. There are a lot of risks involved, but they can definitely be minimized. Being cautious is a very good thing, it is certainly better than rushing in headfirst.
However, being scared of failure accomplishes nothing in the long run and will only hurt your efforts.
As long as you take the time to come up with a good business plan and stick to it, you will be fine.
There will almost certainly be challenges along the way but persistence is the key. Try to identify what about the situation is making you feel fear. Is it just general uncertainty or is there a specific reason for the fear?
Uncertainty is almost always going to be there regardless of what you do. This is one thing that separates a successful business owner from an average worker. All the responsibility is on you as the owner and you are paid based on results, not on time. You just need to decide what the best course of action is and persevere until the end. If there is a specific reason for fear you need to do everything you can to eliminate the problem. Try to look at the problem objectively and make the smartest choice you possibly can. You can not allow your emotions to interfere with your logic.
There are many successful people who would never have enjoyed that success if they had not pushed on even when the situation looked hopeless.
It took Thomas Edison around 100 attempts to successfully produce a light bulb. When asked how he felt about the 99 failures he responded “I did not fail, I just learned 99 ways not to make a light bulb”. This is the kind of mindset you need to be bringing to the table when fear manifests itself.
Acknowledge the fear, come up with a plan, and see it through until the end. You will eventually succeed.