is it wrong?

I knew a practicing Islamic school boy aged 16 worked in a local shop met school girl Catholic aged 17 first handed over change placing it on counter saying he was mut-min (sorry about spelling), next time she came in shop gave change in hand this time holding hand and smiling when no one was round then a few weeks later asked for her mobile number etc started meeting her after work and karate late at night and kissed her as he didnt won't anyone to know but some of his and her friends did - after couple 2 yrs they stopped chatting and meeting up til she and him saw each other at a local train station and they both broke into tears he watched her get on the train with out saying anything and she was watching him and speechless...

is it wrong or are they just being kids