Just emailed one of the Dr.'s at my university to serve as my chair on my thesis committee. I don't know why I'm so scared and nervous. Like shaking nervous. I'm pretty sure he will say yes as he doesn't have any students currently and my project will be similar to his, but that was terrifying. Maybe because this is such a big step and I never thought in a million years I'd be writing an email like that.
He's probably flattered that you asked. Think of it as a partnership. It can be a mutually satisfying and beneficial relationship that can last for years.