In acting there is a phrase called "getting off book," which means no longer using the script, and performing the lines through memorization. Often actors will try to hold on to the script as long as they can, using it as a sort of crutch in the rehearsal process. While script is still in hand the actor has the excuse to look down at it for their lines, or not fully be in their character. Only when you are off book can you truly start to act, truly start to fall into your character, truly make the performance come to life.
Its the same in real life. Some people spend all of their time planning for what they want to do in life, but never actually start DOING anything. Its dangerous to hold onto your plans as a crutch and never move forward to actually living the life you've planned out.
Don't be scared, let go of your script, and take the stage!