First I think it is AWESOME that your family shares the same interest in hobbies. Maybe someday my little girl will play in a fantasy football league with me haha.
I too am zero help when it comes to D&D. I was overwhelmed from merely reading the great comment left lol.
When I was in the military there were a handful of guys that would play D&D on the weekends and I remember their games lasting 12+ hours it seemed. I should have taken that opportunity to ask to play even though it isn't quite up my alley. There is a good chance I will never have the opportunity to play again unless my cousins in Georgia play. They were heavy into Magic the Gathering when we were young and they introduced me to Star Wars among many other things that I wasn't exposed to as a kid focused on athletics.
RE: Just in case you forgot I was a geek... I need some help with Dungeons and Dragons