Do you know - I think Mimi was a mind-reader...
I read the comments and had to agree that yes, she's slowing down...
Then at 11pm I gave her her treats and cleaned her sand pit when suddenly - I didn't even see her get up there - there was a rattling on the lid of her detour and she was standing on her little corner hide doing the thing she used to to say, 'lemme out for play time!' So I let her out and she whizzed around like nothing had changed; even had a climb up the back of the desk (with my hands underneath her of course) like she used to!
So she may be sleeping in later but she's still got some juice in the batteries!
Don't we worry!? She even climbed all over me as normal and made her little "mip!" sounds as she did so (I like to think they mean "I love you!" but they probably just mean "have you got treats?!"