I probably hold the distinction of being one movie star who, by all laws of logic, should never have made it. At each stage of my career, I lacked the experience.
I was asked to act when I couldn't act. I was asked to sing 'Funny Face' when I couldn't sing, and dance with Fred Astaire when I couldn't dance - and do all kinds of things I wasn't prepared for. Then I tried like mad to cope with it.
As you grow older, you will discover that you have two hands, one for helping yourself, the other for helping others.
The most important thing is to enjoy your life - to be happy - it's all that matters.