I don't think you can accept her version of what the therapist is saying as what the therapist is saying. Given that she is now reaching out and agreeing with you when you challenge her fantasy version of events, it seems like something is happening in a positive fashion.
I'm sorry about your D, but perhaps this will give you some perspective. I didn't date at 15. I didn't date until I was 21. I married the first person I dated after knowing him for less than a year. We have been married 26 years in December (3 month waiting period so pretty clear we are traveling through one more anniversary).
I wish I had dated other people. I wish my first breakup wasn't at 46 with two kids, a mortgage, etc. Your D will learn that she will survive this, and in time she will find another boy and learn a new lesson, and probably endure another heartbreak. Those heartbreaks will collectively help her figure out what she likes and needs in another person and what she doesn't.
A great dad and some lovely cookies will probably help a little for now.
