You know, I think you're doing the right thing by announcing this to the group, and I want to congratulate you for having been given this responsibility.
By you posting you will probably be able to network with other experienced leaders and get some support that way.
By merely asking the board it is apparent to me that you are consciencious enough to be concerned that you do a good job, and it sounds like you are concerned b/c of your age. These are good awarenesses for you to have, because you realize that there may be some situations that are going to be new to you. You're not going with the attitude as some know it all.
Also, you were asked to perform this position by people who know you and work with you. Apparently they see something in you that makes them think you can do the job.
Of course, you want to stay in prayer about this, you're probably doing that now, if not, now would be a great time to start.
My advice to you-find out who it is that you are responsible to, who's your 'boss'?(I know someone's going to say it's God, but that's not what I mean)
That way when someone tells you 'what to do' that you know it's from the person that is a leadership position that is supposed to be telling you that, and you're not getting it from 10 different people.
Once you find out who that person is, make sure that you have a good relationship with that person. If there is something that makes you feel uncomfortable about that person, pay attention to it. Don't just assume that someone in a leadership position is right just because they are a leader. People make mistakes.
If there is something about the someone in the band that makes you feel uncomfortable, let someone know about it. Don't try to do this thing alone, you don't have to.