I was a pretty late speaker myself, but now i am a pretty heavy talker. I even some talk in meltdowns. But talking in a social expected way (Saying hello, making eye contact etc) is really hard. The more i mask the less i talk
I am similar. I always seemed really introverted and quiet as a kid since I hardly ever spoke up (and I brought a book with me everywhere), but now I speak more than pretty much anyone since I'm in a more open environment. People probably think I'm an arch-extrovert now. I remember getting really frustrated with people constantly speaking over me when I was a kid, and I was also a stutterer, so I sometimes just didn't bother trying. I have also notice that I speak more when I'm with my mother than when I'm with my father, and my speech feels a bit more unnatural when I'm with him. I'm not sure exactly why as I care about both of them, but for whatever reason I have a stronger connection with my mother.
Yesterday I had a problem because of my mutism. A package arrived I was supposed to refuse so the company could have the item back as they had sent two instead of one. I did not know when the postal carrier would arrive. There was loud fast knocking and ringing of the bell at my door and it startled me so I rushed to answer it but then I could not speak, everything was happening too fast. I use an iPad to type on to talk to people but I did not have it in my hands. I was stuck, watching the postal carrier walk away when I wanted to tell him I do not want the package. It is difficult.
That sounds really frustrating! Hopefully this can be fixed somehow.