This is what I was going to say. I don't know if it would be unethical or not (kind of doubt it, but who knows?) but she may not have kept a list of who wanted to be contacted or she may think it's been so long that you likely aren't interested anymore. Unfortunately, probably the only way to know is to ask.

If it's helpful, my therapist has said that for her "once a client, always a client," meaning that anybody who has been established with her can generally come back if they want/need to see her again later. She wasn't taking new clients when I reconnected with her after she started her private practice, but she still scheduled me right away.