Old Lady Radar

I would like to know at what age do you get your old lady radar? I know it exists because Mildred Hall has it. She can be DEAD asleep, but let me open a bag of cookies.......
For instance, today I seriously need to make a LONG HAUL at Wal-Mart. I know that nobody is going to allow this to happen, so I'll have to wait for my knight in shining armor to come home from the golf course this afternoon. So, what to do until then? OH I KNOW! I'll lay out in the sun....yeah.....that's what I want to do! I gather my "laying out supplies; phones, book, sunglasses, hat, etc, then I put on my bathing suit (grunt). I move the Moma monitor to the deck so that I can hear her grunt and carry on in her sleep (and know when she gets up). I make sure the front door is locked, feed the dogs, and get to my chair. AHHHHHHHH!!!! What's that? I hear her. She's opening a drawer. She is grunting....good sign. That means she is still in her room. Time is ticking away. I listen....................she is moving around in her drawers. Maybe she is only changing her diaper. I listen intently........nothing. SHE IS UP! Of course she is.....time in the sun? 10 minutes.
Now that she's fed and gone back to bed? My daughter and her friend are sunning on the deck in MY chairs. Sigh................When I get old, I am driving somebody to drink. That is a promise.