When do I send it ?

So my ex has been swinging between signs of justifying her story that I was wrong (we both were wrong but she only saw her hurt) and that I left her and she's heartbroken and one side she's giving me indirect signals of longing and missing. I had already been wanting to send a message before she did all this, but now I'm like if I send it rn, she'll be like I'm reacting to her. If I send it later after a few days, she'll be like he doesn't care for me and has moved on. I honestly don't know what to do and am stuck. Can you guys suggest something ? It's a message that invites her to talk and discuss about what went wrong and what our future could be. A calm talk.