Yeah it's hard to calculate when reality sets in. There's also a bit of reluctance from me as a lot of expectations follow me when I reveal my age even when I don't look like how old I am. It's like suddenly you feel that you are not so welcome in some conversations any more or people keep you out of their circles because they presume that you don't fit in.
I've gotten way past that and while realising that my body isn't what it was physically 20 years ago, I'm treating age as just a number and if one has a problem with that, it's really their problem not mine 🙂