I just turned 22 and i know how that feels mate. Speech therapy never helped me in the long term. November of 2019 was the worst in terms of my speech. In work meetings i could not say what i wanted and made awkward face reactions (still doing but a lot less) to be able to spit a word. Something that has helped me a lot was listening to the "Stuttering Mind" Youtube channel. It's from a man called Rama Siva who's on his 40's and he pretty much overcame stuttering. He created a facebook community called Stuttering Mind Community. Anyways, basically what i learned is that to be able to be better at something you have to practice and i certainly was not doing that. One thing that everyone pointed out at this community was that practicing your speech out loud was crucial. It's common practice for everyone in the community to upload videos of themselves talking as well. Since December i'm reading 10-15 minutes out loud from a book while also trying to practice diaphragmatic breathing throughout the day. 2 months of practice and i can tell that with my family or friends i'm far more confident and barely even stutter. I still stutter at work though but far less than i did 2 months ago.