Even at my age (22) in a stable relationship of 4 years with a carreer, there are songs, places and people who make me smile about my mid teenage years.
I long to be able to have the wreckless fun we did on scramblers in local woods, camping in strange places with nothing but a mates paintball gun and a pair of walkie talkies to keep us entertained. Attempting to 'race' eachother and other bikes/cars on our mopeds, and wasted afternoons in the sun on half college days.
Its not an age thing, it is in my opinion one of the greatest gifts and signs that you have enjoyed those moments. A reminder that life is there to be lived and made the most of each day! Ooh how profound!