Ann
You are in a tricky position but it may be similar to one which many of us have wrestled with. First, only you can determine what is best for you. Second, only you can set your course, write your story, and accept and express your truth.
It is natural to have fears, to question your feelings and to second guess your self. As you are already working with a therapist you are already seeking expert help in enabling you to determine how best to live your life.
As someone who at 61, has spent more than 10 years on low dose and transition dose hrt I have had similar thoughts to you. In my case I had a simple choice - did I want a life where I accepted and lived my truth or one in which I was somehow less than I could be. Did I seek truth, uncertainty and euphoria or denial, dysphoria and a compromised life?
Finding the answer and deciding to transition was the most difficult thing I have ever done, even though my friends and therapist say that they have known for some time as to where I would head.
As I reflect on this somewhat tortuous and attenuated process, I am fairly certain that I was internally transphobic so self acceptance and self love took a while. I am also clear that my desire to support, love and protect everyone in my life, rather than to nurture my self, also hindered my progress. I decided to take my time to question my identity, seek multiple diagnoses and to find a safe space in which to transition. This meant that I publicly identified as non binary and presented as androgynous.. and this is ok. In my case my journey is likely to be more important that than my ultimate destination.
So where am I? Well, 3 weeks ago, my wife of 33 years asked for a divorce. Strangely, after initial distress and hurt, I am good with this. She said that she was holding me up, knew that she couldn't live with a trans partner, but as her best friend wanted me to be happy and to be a major part of her life.
My take away is this. Be open and self loving. You have one life and one truth. Seek to find, love and to express this truth. Don't stress over your age or the schedule. This will take as long as it takes. You are the author of your story, the hero of your quest. To have no regrets, to have found and to have lived your life purpose is important. A human incarnation is precious. Don't waste it.
Ann, I hope this helps but ymmv and every one of us has a different life experience, find a different answer and must author our own life
Safe travels
Aisla