thanks all for your great opinion.
Understand that it will be better off getting training and PPL license oversea (e.g. US/Australia). Right? then it would not worth to take the trial introductory flight in HKAC
...
I come across a company called JetOne which offer ground school in HK and arrange training and exam in LA. Maybe I will think about it (but the $ and time committment is big)
By the way, what is "GA" anyway?