It is easy to be reserved in the face of new life challenges or problems. However, when approaching these new situations do not focus on your actual cognitive and physical ability to complete the objective. Instead take stock of your previous experience in overcoming challenges, specifically your problem solving and reactionary skills, and harness that knowledge in your upcoming endeavor.
Consider also how often situations turn out differently than what first analysis might reveal. Tirtiary understanding can rarely be trusted. (This counts for both yours and a third parties first analysis). Knowing this, when approachingy a new life territory, fortify your existing strengths and don't worry about he unknown.
Those lacking self confidence in the face of bigger life problems may have an easier time improving by focusing on these two skills, instead of letting the looming problem dominate their thoughts.