Can I put "since" in the middle of a sentence? Does it sound awkward?
"My dad used to teach computer sciences at ABC.It was weird for me and Mario since he was trying to teach a 5 month-old Joe how to play computer games."
Would you say "me and Mario" or "Mario and me"?
Your sentences sound fine to me. Some will tell you to put me after Mario, but conversationally 'me and Mario' is what you will hear all the time.