How do i tell my unsupportive mother im engaged?

Im a 26 year old women with two children and just got engaged to the love of my life. Im so incredibly happy it feels like a dream! However, my mother has not been too happy. Shes always been very controlling and negative to everything good that happens to me in my life. A year and a half ago i moved 45 minutes away from her out of the city to a small town nearby and shes been mad at me ever since and thinks im taking my kids away from her when in reality i moved for a better life as the city was getting too expensive to afford. She has been spiraling alot and lashing out at me for not prioritizing her and doesnt like that i put my kids and partner first.

I made sure to tell my close friends about my engagment first because i know as soon as i tell her she will plaster the news publically all over facebook for the world to see even if i ask her not to and il lose my chance to tell people myself (she always has to steal my spotlight, i made the mistake of telling her about my pregnancy with my second child before i was ready for it to be public knowledge and she "accidentally" told the entire family and everyone in the world within a day 😑 robbed me of my announcement) I havnt told any family yet because i know if i do she will FREAK and cry i told grandma/dad/cousin/etc before her and they will definitely tell her i told them first but then if i tell her first she will INSTANTLY be telling everyone else before i even get the chance to tell anyone, like if i were to send her a text announcing my engagment first and then right away sent texts to other family about it i wouldnt be surprised if she even managed to call them and get to them first before they even see my text but i guess thats a chance il have to take to keep the peace.

Im definitely telling her over text, we do not call eachother and we do not see eachother often because shes really uncomfortable towards me and guilts me for never seeing her when i do see her. Ive seen her once this year around new years. Im full on expecting a negative response no matter how i word this, shes already mad at me currently because i havnt answered her texts in 3 days and is sending me alot of crazy messages saying she has a feeling something bad happened and she thinks im not safe and to answer immediately.... which she does often if i dont answer her right away and theres no reason for her to be concerned im just at home with my family. So i have to find a way to diffuse that or maybe i should ignore it and just send a message like "Hey i was just spending time with the family! We had a wonderful weekend _____ and I got engaged!" Im not really sure how to go about this. I dont know if its a good idea to say something like im engaged and happy whether you like it or not because then she will see it as me attacking her unprovoked and make me the bad guy.

Im so happy and its a shame the stress from how i know my mother will react is dampering my moment. Does anyone have any advice or input on ways i can deal with this? Id love a outsiders POV on the best way i can approach this situation to keep myself happy and as stress free as possible while also ripping off the bandaid and letting my mother know whats going on.