Knuckle up. Get fit.
Brazilian Jiu Jitsu (BJJ) Promotes the concept that a smaller, weaker person can successfully defend against a bigger, stronger assailant by using leverage and proper technique, taking the fight to the ground - most notably by applying joint and chokeholds to defeat the other person. Knuckle UP Martial Arts is a certified Jean Jacques Machado School.
As a practice that will help you defend yourself against opponents of any size, Brazilian Jiu Jitsu teaches the techniques needed to accomplish this.
Your BJJ classes will focus on techniques such as proper leverage to take a fight to the ground - this will allow you to apply joint locks and chokeholds to successfully defeat your opponent.