How do you know when you're getting old?

So, how do we know when we're getting old? I ask that question because I think I'm at a certain age when the answer is obvious! Off course I'm not old!
Am I going grey? Yes (every day I was counting two more grey highlights so I dyed it "darkest brown" though it does look black, so I've decided I'm the cross between a biker chick and a rock chick).
Do I like pottering in the garden? Yes but that doesn't mean I'm old, does it?
Do I wake during the night just to use the toilet? Yes, but that's because I have cocoa before bed!
Am I turning into my mum? Don't be bloody (mum wouldn't use that sort of disgusting language) stupid! I don't care what my (nearly 21 year old) son says, I'm not turning into his grandma, I hope he wets his self now, he should've " tried "before he went out!
Do I go to bed late? No, but that's just because it'd put me out of my routine.
Am I forgetful? Well, sometimes maybe (not all the time as hubby thinks)!
Do I easily get confused? I make mistakes sometimes that's all, most people get Tuesday's and Thursday's mixed up, don't they?
Do I carry emergency pants in my handbag? Doesn't everyone, my mum does so I guess everyone does, don't they?
So, my conclusion after all that is? Erm, maybe a little bit but only a little bit.
Tomorrow I'm going to out and do something rebellious, just to prove to you all that I am not getting old, unless it rains of course, and then I'll wait for another day!
Me old? Huh! (oh blast, my cocoa has gone cold).