Those of you who went to therapy, do you still feel like you are yourself?

I am going to start therapy next month, I know its the right decision but i have a textbook red flag concern. I had really fragile sense of identity in all my life, so I really try protect whatever makes me me, and what I understand about my identity. A lot of things that I did were connected or caused by borderline, so I feel like a lot of these things are part of who I am. I am really scared of not feeling like myself, or a shallow version of myself if therapy changes me. If you felt the same, could you share your experiences with it? Is this a reasonable thing to be scared of in this situation?