I first saw the Star Wars SE in theaters at age 8. I didn't like it. Darth Vader weirded me out, and the fantasy elements like the Force turned me off. I was more of a hard sci-fi fan, and even then the non-realistic elements bothered me. (Why didn't the x-wing pilots wear spacesuits?!?!)
My cousins later encouraged me to watch ESB and ROTJ on VHS at age 12. I really enjoyed ESB. I suppose at that age, the more mature story of ESB was able to appeal to me. Unfortunately, I don't remember if the father revelation was a surprise to me. ROTJ was fun, but I knew I liked it the least. I rewatched the trilogy many times that summer, and my cousins even gave me the VHS set.