Online on forums, social media, on dating profiles and even in real life people claim to look younger than their age, they are X age but don't look it. They get ID's in the supermarket buying wine.
I am always highly sceptical because I've know people who say to my face how they look like they are 25 when they are actually 38 because they have no lines or wrinkles when I am looking at them and thought they were actually in their 40's and they have obvious wrinkles and grey hair, people are delusional! Honestly the capacity people have to delude themselves about anything is quite staggering and I have never met someone who claims to look younger and it actually turn out to be true.
When I was younger I thought some older people looked younger so I once thought a woman when she was 49 was closer to 30 but that was because I assumed all people of 49 looked "old" which isn't the case at all and looking back she looked great but she also looked her age which is fine.
Going back to the first case where the women was convinced she looked over 10 years younger, what could I say I just said yeah you look great and its the same anytime anyone makes that claim. People aren't going to dispute it.