Someone once asked...

I feel like I need therapy for talking to my therapist I have autism-caused selective mutism and somewhat severe social anxiety I just can't force words out of my mouth when I'm uncomfortable I don't know when to bring up things to my therapist because I don't want to be rude and interrupt her but she probably already has things planned out for the session so I don't know when to tell her It's a lot easier for me to type things than say them

Someone answered with kindness...

The session is about you, not the therapist. It's very considerate of you to care about their session plan but you will do more to help their plan by doing your best to open up about these issues and concerns. It might take time to express this and work through it but hopefully it will lead to improved results and understanding for you.