If you are a boomer this question is an invitation to ageism. Equivalent to racism. Too drastic you say? When you tell your age and they reply “You look good for your age.” You have now have accepted that you accept society’s cultural prison of numerical age, declaring your limitations, humiliating yourself.
Their positive reply is like saying “Wow you are smart for being a mentally challenged person.” That’s crap.
So how should you answer? Tell them “I’m 16 inside actually. How old are you?”.
That’s a healthier place to reside in this world.