I don’t know anything about your family situation, but if this is the first time you’re stuttering then I’d ask family members if they’ve also stuttered before. It’s not uncommon for it to pass down genetically. Also, you could just be having a stressful week or be undergoing a change in routine. On top of that, as a fellow 17 year old, I can say that mood swings and hormones can also make a stutter worse as well. But if this is the first time you’ve ever stuttered and it’s coming out of the blue, I’d definitely check in with a speech pathologist about what to do from there.