Hi there. For what it's worth I totally agree on Stella's comments. It is difficult to wait, especially when you're emotionally ready but the mechanics of the appointment aren't timely.
I'm in a similar position now. I completely understand the window of opportunity metaphor. I've had therapy multiple times send to derive best benefit you do need to be in the correct fre of mind, as it's hard work.
I'm writing down bullet points and a spider diagram for when I'm seen. It will deffo jog your memory and help the therapist, and you when you have your sessions.
Good luck and chase them up if needs be.
Xx