I never really figured this out until after high school, but my stuttering is about 90% psychological. If I'm being silly or making a joke, I'm almost totally fluent. For me, it's a matter of putting myself in a state of mind where I'm confident just in general, and not worried about the words coming out of my mouth. I have by no means mastered this, but I know it is definitely possible. I do improv theater as a hobby, and whenever I'm in a scene onstage, I have no speech problems. Something that might help you is, when you have to go in front of the class, try talking in a slightly different voice. A little higher, a little lower, or in an accent! Even letting your class know at the beginning that you stutter would alleviate some stress, if you feel comfortable. I've gotten more OK with just telling people I stutter if I'm having a hard time speaking. They usually seem curious about it, instead of freaked out (like I feared). Anyway, I know stuttering sucks, but there are ways to get around it. Good luck in your sophomore year, and PM me if you have questions.