Do you speak another language or have family history? I also started stuttering very late and I was very confused on why till I went to speech therapy and was told that because of my family history I was meant to get it :/ I started to stutter when I learned English which was about 14 years ago and ever since. My advice is go to speech therapy and see if they can help you. For me personally it didn’t and I thought it was a waste because mines was genetic