It might also be worth thinking about your hopes for therapy and the course of therapeutic change.
For example, you want your dissociation ironed out first, and I understand that desire but your dissociation serves a purpose in keeping you safe, in stopping your system becoming overwhelmed when triggered. That means it may actually be one of the last things to settle because your window of tolerance needs to be exapanded to stop your system "tripping" when your feelings become intense.
A therapist can help you ground yourself and teach you ways of tolerating strong feelings, but your body will let go of the defence mechanism when it's ready to, when it doesn't need it any longer. So it may not be the first thing to be iron out, if that makes sense.
For me, I'm nearly 3 years in therapy and still dissociate at times of high stress, the differences are that it happens much less often than it did, I can ground myself more quickly and I understand it as a defence and so don't beat myself in the way I used to - which actually makes it pass more quickly. Treating trauma/PTSD isn't a case of picking off symptoms and "curing" them, it's working with your whole system which has been traumatised as a whole and needs to heal as a whole.
