I didn't really have any. I knew about Christine Jorgensen and Renée Richards, and then, later, about Wendy Carlos, the genius of the Moog synthesizer. But they were newsworthy celebrities, so I thought being trans was only for newsworthy celebrities. It never occurred to me that normal people could be trans, or that I could follow in their footsteps.
The first trans woman I encountered in real life, and whom I thought I could maybe be like, was an astrophysicist who gave a talk on her research at a scientific conference. I won't give her name, because I believe she wants to downplay the fact that she is trans. I was impressed that she had the confidence to present a lecture in public and not have it be weird. It was almost like trans people could be ... normal! Gasp! I started my transition less than a year later, after having signed up on this site.