I don't know your situation and I have a few questions.

Why is it that you can't involve your parents? Are there community services in your town that could help you? Not all services require you to be 18 or to have parental permission; you can call anonymously and talk to someone and see what is available to you. When will you be 18?

I wonder if the arrangement could even be helpful to you because of your very understandable reservations.

It sounds to me like it could be a generous and selfless offer by the retired psychologist; but by today's standards it is not above board. It would be considered unethical even if offered in generosity and a true and unselfish desire to help.

You found one solution. Perhaps you could work on it again and find another solution that would be more appealing and comfortable for you?

I hope everything works out for you no matter what you decide to do! Keep us posted.