Sheffield United in the FA Cup, the infamous balloon game. Parents took me. Was 13, I think.
Had a pretty sad experience after the game was done. Walked out of the away end straight into a brawl onto Bramall Lane itself. Our car was parked down on the industrial estate to the south of the ground but there was loads of fighting in between. We turned round to the steward - just my parents and me, a little scrawny 13 year-old - and asked if we could take shelter on the concourse until the violence was done. He said "No" and put his arms across the entire doorway to stop us getting in. Sent us north round the other side of the stadium and through more clashes with fans and police before we eventually got to the car and drove away. Put me off away games for absolutely ages.
First away game on my own was when we went down to Leicester in the FA Cup in 2011, the Neil Young game where we all had the black and red scarves. Quite an emotional day considering we were playing Leicester as well. After that, I only did a couple more away games and they were both during the first title-winning season, 11/12. Bolton away, the 3-2 win when Dzeko scored and Tevez got booed onto the pitch at the end (the Reebok is a shithole and I never want to go back). And Wigan away, the 1-0 win when Dzeko scored that header in freezing conditions. Just stopped bothering after that because you needed astronomical amounts of loyalty points and all the Lancashire teams (Bolton, Blackburn, Wigan) got relegated and some health issues meant it wasn't as easy to travel.