I switched school when i was 13, i had a great teacher that adviced me to speak at the first opportunity. I think he said that because he was afraid I would avoid talking and dont participate in class room discussions etc. I followed his advice, and more importantly for me it took the edge of my anxiety about stuttering. If i try to fake fluency it's an impossible task that will cripple me completely with anxiety through the roof. Speak as soon as you can and get it over with. Obvioisly i still was afraid of stuttering in front of people, but there's different levels of fear/anxiety. Best of luck:)