Ooh. Well.
Starryprince you do not EVER have to forgive your grandma. I mean you are welcome to if you want to.... but if you never forgive her for the criminal and obscene acts she committed against you then so be it.
Why on earth would she tell you to talk about your abuse next time you meet? Who one earth is she to dictate your timeline and pathway of healing?
The things you have written about your T would be more than enough for me personally to not return to her again. From what you have written she is actively disempowering you. I don't find disempowerment helpful in any way at all myself.