I'd think that you need to focus on the bigger picture rather than contemplate failing or your chances of making a mess.

First, if they took you on, then they have the trust and belief that you have the potential and ability to grow into your role. (And since any production is somewhat uniquely different from others, you do need to grow into it.)

Second, if you are into getting experience in the field, I would assume that stage managing is a field of work that you envision doing in the long term so this challenge is all in the arena of getting more experience.

Third, knowing your weaknesses is good but that's all they are, if you are aware of them you can actively learn to do things that don't let them be in the way of achieving your goals.

Fourth, I think that you definitely have to stick with basic principles that guide your work i.e. to know your part and more through and through so that people know that you are reliable and professional. It's not about bossing people around. Real leadership I think is being able to take the lead. And all in good faith, everyone wants to make a production work rather than cut people down. It's always a team effort anyway.

As you stated, you are going to be the Assistant Stage Manager, this will give you a great chance to work with and observe the SM and learn.  They are not going to just let you run off on your own. 

Originally posted by pdavis69 First of all you need to lose the "not a take charge kind of person" attitude.  Stage managering is alot like herding sheep.

Yes POB, big fan.  My Father made me listen to old radio shows and I got hooked.