Good luck man! Consider disclosuring it before hand to them, it'll make you less nervous and maybe they could give you a bit of extra time. Also try to relax, being nervous could make you build weird phrase structures or use the wrong verb, which will penalize you; and stay vigilant of your pronuntiation. If your stutter make you butcher a word you know how to pronounce and they notice, explain your stutter something cause that and pronounce it right.