Happy Birthday?

On the morning of my birthday, my mother texted me this:

Hi Dave, Happy 46th birthday . . . have a good day . . . I can't believe in four years, you will be 50, I will be 75, hopefully, and Alex will be driving on his permit . . .

and I feel like the tone of this text is a breach of birthday etiquette, as not only is there a reference to my mother's mortality-- and she's perfectly healthy-- but the text also thrusts me four years closer to my own hypothetical demise, for no apparent reason-- and four years is a long time: longer than my wife and I spent in Syria, the same amount of time it takes most people to get a degree, and so I wanted to text back (but didn't) a message in this vein: "That's true, and in fifty-four years, the bulk of the East Coast will be underwater and we'll both certainly be dead."