Hello Jackie. Welcome to the site. I am an older trans girl also. Like you I started HRT without telling my wife. I had been out to her for 2 years. Six months later after starting HRT she asked me if I was taking hormones and I said yes. When asked why we had not discussed it first (same as getting her permission) I asked her would she have said yes to my taking hormones if I had asked her first. And of course the answer was no.
As trans girls we have to do whatever we can to survive. No one else will do it for us.