Minecraft server owner believes I'm older than I really am and I need to skype him?

The title is self explanatory, but I guess this is kind of important, the owner of a Minecraft server that i got to know and his small little 20 view twitch stream would like to contact me over skype about oping me. Now the problem is that he thinks i'm twenty when I'm really third teen years old. So I guess it would really decrease his thinking in oping me and might change his mind, it's a fairly big server so I don't want that to happen. Now I'm pretty mature when it comes to things like this so I'm not like any little annoying kid on the internet; there are people like me but I'm in a predicament here because I could maintain a good conversation with a twenty year old if needed. I jut don't want him to see me over skype and changed his mind upon seeing me. Any ideas on what i should do or encouragement would be great thanks.

Just ask your dad or someone older to talk to him. If not you could get in the Skype call and have your Mic not work. Just be honest, this is the problem when you lie, it gets you in more trouble then being honest in the first place.

Tell him you don't have a microphone.
Otherwise just say that if he trusted you enough to OP you without knowing your age then being 13 would change that

This is a good example of why you should not lie about age. You should be truthful about your age. 20, 13 or 56, it shouldn't matter. Just tell him the truth and he should understand. If not, abandon the call. As it is a waste of your time.