Not "coming up on"! You reached that point about six months or so ago. From now on, you'll be getting ever closer to her. In thirty years time, you'll be older than she is now and two-thirds of the age she will be then. (One hopes she'll still be around.)

That sort of milestone is disconcerting, isn't it? I'm now older than my mother was when we moved to this house, lo these many years ago. Mostly, I don't feel it; but then it catches me unexpectedly in the knees.