There is an adage that it is never too late to learn. Whilst this is true, retention of information is definitely easier during formative years. Growing up, it was a constant struggle learning Mandarin as a second language, in part because English is a lingua franca in my community but more importantly, memorising each and every character is an absolute test of memory skills.
But I have gradually learn to appreciate the beauty of the Chinese scripts and nuances of Chinese vocabulary. So after 25 years, I will be picking up a Chinese novel and putting my dusty dictionary to good use.