What a thoughtful teacher you have!
Are you planning any retirement shindig for her/him?
It would be neat if you could round up former students, have a piano playing party of some kind. I know I would be thrilled if my students were so inclined.
As for your question, out of respect for your current teacher, I'd go ahead and visit the new teacher's studio, but I'd wait until retirement to actually begin lessons.
I actually don't know where the other adult that she used to teach lives anymore, so the only "shindig" I would be able to do would be to take her out to lunch along with a former student's mom. The mom doesn't take piano but her kids did and they are at college or in a different city. But the three of us do occasionally get together for lunch.
Thanks for the idea of at least visiting the new studio and then waiting until the retirement. I was thinking that I'd finish up with the end of the school year as the two other students will be moving on to college in the fall and that would be a natural break in things.
But - here is what happened yesterday that caught me off guard:
I had in the past asked my teacher what she would do with me once the other 2 went off to college. At the time I asked the question my teacher said she would still continue to teach me.
So yesterday when she brought up the fact that she found me a place in another studio, I was taken off-guard. But she did say for me to think about it. But she also said I could go at whatever time that I wanted since the other teacher said I could come at anytime. It feels like a gray area or that I am not reading some subtle hint, or I am just imagining things. I guess I am a bit off-balance.
But your idea of meeting with the new teacher and then transitioning when the retirement actually takes place sound like a reasonable approach.