When I was sixteen, I simply thought that bikes were really cool and I longed to have one myself.
I just thought bikes were really cool when I was sixteen.
I was about sixteen and I just thought that bikes were really cool and I admired the sport.
「16歳の時に単純にバイクがかっこよくて憧れた」＝ When I was sixteen, I simply thought that bikes were really cool and I longed to have one myself. / I just thought bikes were really cool when I was sixteen.
When did you get into sports bikes? → I was about sixteen and I just thought that bikes were really cool and I admired the sport.
ボキャブラリー
when I was sixteen ＝ 16歳の時
simply, just ＝ 単純に
thought ＝ 思った
really cool ＝ とてもかっこいい
longed to ～ , admired＝ 憧れた、～したかった
イギリス 
