It's oh so difficult when there's those in one's family that are hardwired to be intolerant. I almost suspect that it is its own growing pain, a unique pain that not everyone in society can understand where it's not everyone's journey. Keep in mind the silent and not so silent supporters surrounding you. Sounds like your parents are stressed over the great potential for your grandmother to not only reject you as you are, but the anguish that could bring them because you are their child? It's a delicate line they are walking. Yet, they, also aren't alone.
((((gently hugging))))