There are plenty of people here who'd just love to be 25 (or even 30 or even 40, etc) again ;-). However we all still think that we're young anyway ;-)
When my daughter turned 39 I said she was in her 40th year, that didn't much please her!
Remember you have 3 ages
your passport/birth certificate
your head age
your mirror age
I prefer the head age, I realised today that I'm morphing into my late mother in law to whom everyone was t'owd chap. I mentally thought of a lady in church as 'the old woman' but she was possibly younger than me!
I don't think it is, you'd have to live another 20% as long as you have to get there, and 20% is a lot. (Like saying you were nearly 90 when you were actually 75).
When I say is it nearly 30 I don’t mean scientifically or mathematically I just mean if someone told you they were 25 would you think they are nearly 30