My mil is 62 this summer.
You would think she was 92.
She's always been helpless - can't pack her own suitcase, operate a shower etc.
She's also always been a poor eater.
She looks ancient. Eats like a doddery old lady. Goes to bed at 9. Sleeps in the early evening and gets up at 9am.
Zero energy or zest. The only thing she has energy for is talking about grudges! 
What could be the problem? She says she's not ill. Or is this normal? I just compare her to my mum in her 80's and my dad, 76, and they are positively full of vim and vigour in comparison.