If you never push past your comfort zone how will you ever know what you are capable of? Don't hold back. Give it everything you have or don't waste your time. We tend to view risk-taking negatively, often regarding it as dangerous and even unwise. But while some risks certainly don’t pay off, it’s important to remember that some do. But we could never know if something could pay off if we weren't willing to push past our perceived limits.
"Tomorrow isn't promised" is a quote that most everyone has heard. This quote isn't meant to be sad or depressing. It is meant to be a reminder that every single day should be viewed as a gift. How would you treat those closest to you if you knew it were you're last? What would you spend your time doing? How much effort would you give? How much time would you "waste"? If today were you're last I hope you would go to bed exhausted knowing you gave everything you could.
NOW is the time to be great. NOW is the time to take action and get started. There is no better time than RIGHT NOW. The only thing that you must do is start. Even the greatest were once beginners. Realize that you have to start somewhere and then make it happen.