You have to do things that scare you. Comfort zones may be a wonderful place, but nothing ever grows there. Imagine being too scared to try something new, and choosing to be in your comfortable situation for months, or even years. Will anything change? Probably not.
Being content is fine if it makes you happy, but in my case -- in my story -- I had reached a point where I had no choice but to do something completely radical to change my life and take back control of it. If I had stayed with what made me feel comfortable, I never would've been happy. I would've been miserable, continually, until I felt like I had nothing else let to be live for.
There will be moments that you encounter throughout life when you become nervous, anxious, scared, fearful of what could happen -- but it is absolutely possible for you to harness those feelings, and look at them as signs of what to do moving forward -- instead of moving away from them.
So if the idea of doing something scares you, maybe you should actually do it.