You need to practice it a lot... I don’t go to college anymore but the best in my opinion is practice in an empty classroom... I don’t know if you’ll be able to find one but when I was in college I used to practice presentations with a friend and it helped me a lot. It didn’t fix my stuttering but it made things easier... The main goal is repetition so that when the day comes to present in front of the class you’re as comfortable as possible. You want to feel so comfortable that it almost feels like you’re just at home speaking out loud. I know it’s hard and stuttering isn’t something we can just magically fix but practicing like this helped me a lot.