granite, a great start, honest and clear! but I hope you don't just 'leave it alone, agree to disagree'....I hope you and T can come to place of truly understanding each other, you to understand what she meant and she to understand what you feel/know to be the truth of your reality, even as a baby. Maybe your letter will help her understand you better and understand how you feel about trust in your life...and you 2 can be more on the same page!
I think it's a good insight to say that maybe you trust more now than when you were 5.....that means that you are growing in trust now! I think you are showing trust in us to share that letter and I feel like it's a honor that you have shown that trust. I think T will see it as you showing trust to give her that letter and that she will be honored, too!