I have an immortal woman who's been living since the 1900s. It's the 2010s and she still looks like she's in her 20s at peak physical health. She has abnormal levels of physicality to the degree that she can easily outperform even Olympic champions despite lacking the musculature needed for it. She's also beautiful enough to be a supermodel and actress. She's very indulgent and doesn't really care too much about attracting attention.

Of course, she still does hide the fact that she's immortal but she only does this halfheartedly.

1. I need an excuse that she'll use everytime someone asks about her abnormal traits. She'll attribute it to some medical condition with intimidating jargon that sounds a little plausible but collapses when thought about more deeply. What would it be?

2. What would justify her lack of worry about anyone finding out or caring about her immortality?

Setting is modern day Earth

1. People generally don't actually know why they're in good health. The world's oldest people attribute their longevity to all sorts of things - a spoonful of olive oil every night before bed, a raw egg every morning after waking up, etc. Diet culture and health fads are plenty full of intimidating jargon that collapses on closer inspection. She just mumbles something about omega-3 when asked.

@Dmyt I mean, I don't even know many people who have been asked or even asked something like "How are you so strong and/or beautiful?!" I've been asked how I got so tall (I was 1.85m / 6 f when I was 14 years old) but that's not really answerable. Nor, do I think anybody expected a serious answer.

If somebody asked me how I got so beautiful (in a bizarro alternate universe I actually was), I'd probably just say it's good genes or something. And if somebody asked me how I got so strong, I'd say I train. Even if I don't.

I mean, you can certainly concoct a more complex story, like "I used to be the star athlete at school" but...it's not needed. Like, nobody would care for real.

@Dmyt She's old. Old people start giving less fucks. Probably as simple as that. There are probably things to worry about but maybe she just doesn't care any more.

It's not like it's even unique to old people. There is plenty people who go with "it hasn't happened to me yet, therefore, it probably won't happen". If she avoided being recognised, it could just be down to human nature.

Going back to the immortality - a surefire way to make sure nobody finds out is to have a detailed explanation. Doesn't need to be real, just talk about healthy food, fibers, maybe toss in some essential oils and such. I assure you, that anybody IRL who starts going on about these, isn't really listened to. People would just politely wait for a gap in the conversation and either leave or change the topic.

Also, even if somebody were to not immediately try to forget the whole tirade about health lifestyle...they are extremely unlikely to try it themselves. Tell somebody to detox two days straight only drinking disgusting shakes and they'd not do it. But even on the extremely rare occasion somebody does try the nonsense she tells them, it won't work. And again nobody would really attribute this to "she's immortal" but probably lots of other things.

maybe she sells the disgusting shakes herself. does she need a day job?

"i look this good at thirty-nine because I drink Skub every day!" no ma'am you look this good at three hundred because you're a space alien.