I thinks it’s to do with mindset and environment. I speak confidently and fluently when I’m by myself. When I’m with close ppl the stutter is still there kinda and gradually goes away. I think mine was caused by trauma and anxiety. I suggest: mantras, meditation, yoga, getting a job where ur forced to work with ppl In uni I was kinda forced to talk to ppl and shit and I think that kinda helped me bc during these past two years I was trapped at home and didn’t go out much. But recently as I said I forced myself to go outside, smile more, got a job, mantras, meditation etc…. From nov-dec I’ve been talking more and trying not to overthink and worry. And tell myself I don’t stutter. It’s helped a bit but I do tremble over my words here and there. I think it’s possible to overcome it in my case. I’m not much older than u too so if u wanna practise message me anytime ✌️