I'm not old enough for this!

So I've been teaching for approximately 1.75 years now... But somehow I've got a college intern in my class two days a week, and I'm supposed to help the new long-term sub on our team lesson plan until she gets on her feet. I'm definitely willing to help in those ways, but I sometimes feel like I'm not old enough to work with adults yet! Most people probably feel like they're not old enough to work with kids yet, but I've always been a little backwards.