我曾经的少年已不再是我的
[wŏ céng jīng de shăo nián yĭ bù zài shì wŏ de]
'My former youth no longer belongs to me' conveys the poignant realization of how a youthful past (or someone who embodied that period) cannot be reclaimed or has grown distant and unrecognizable. It signifies change and loss over time.