It takes time. You're undoing a lifetime of transphobia on the path to self acceptance. Even when you know who you are, the entrenched stuff takes time to undo. You'll get there though.
That being said, I've got aphantasia, so no mental images of myself, past, present or future. It took me time to accept myself and feel comfortable with my labels, without a future self image to work towards. But, I got there.