I would give her a chance to respond. She will more then likely become aggressive because she's not getting her way. If she becomes aggressive and starts raising her voice tell her you will not have this conversation until she calms down and speaks to you like an adult. If she refuses walk away.
If she rebuttals with anything other then the offer you presented tell her that you have thought it through and your decision is final.
My 2 cents. I would trade out speaks to like an adult with speaks to with respect or something similar. From my experience when I would tell Ex that I want and adult conversation or be spoken to as an adult, she would take that as a dig and would try to escalate things.
H(37) W(35) D8, D5, S3 T20, M13 BD 8/31/18 EA Discovered 9/13/18 Mediation 10/3/18 W files for D 10/12/18 W moves out 11/10/18 EA confirmed 12/25/18 D Final 1/10/19