Doesn't matter if you increased your alleged age for 5 years in past 2 months

Just be careful not to make those typo in your university assignments and or high school homework
But if you, hongkongtraveller, shows up at lounge and look younger than 21 (which i presumably u do) then they can refuse you entry. It happened to me when I was back then in your age

Also, CX will refuse to serve you alcohol if you look under 18.
What you can try is to grab someone who's over 21, and ask them to go into lounge with you, and claim this individual will be responsible for your action. Then could let you in at that time.