I'm 39, only child, only have my mum. Very close to my cousins but have a detached relationship to their kids - I'm the youngest of my 'generation' so I'm closer in age to them, but I don't really even speak to them much.
Single, very much single, I will definitely have any children of my own. I wouldn't mind if I met someone with kids, so I guess that would change things, but on the hypothetical stance...
I'll have a very very good pension, although I don't plan to retire too early as work is something that keeps me going and sane. My plan when I retired is to sell my house and join one of those 3.5 year cruises and travel the world, health permitting.
And then what? With no one, I'd love to fulfil all my dreams of travel and then retire quietly to Switzerland and end it all... but do we think it will be allowed/acceptable by then????