some things you describe that she does, like not know her own emotions, so she changes personalities over time. I do/have done that. I am 51 now, so things are much better.

But when I was young, I changed who I was, thinking it was growth. But trying to be different people, in order to find myself.

She is learning herself, and experimenting. (BPD?)

She will continue to change. Mutable.

You are looking for a fixed sign, astrologically speaking. You want someone who has found themselves. For you, mutable people will seem - insincere.

Love the memory, to give her a last gift of the idea she was appreciated, but move on. Keep listening to your heart. Don't argue with it when you don't like it's answer.

<3 Peace