The question of whether size matters is often raised in martial arts. In short, the answer is yes, height and weight play a huge role in martial arts and self-defense. Self-defense instructors who want to scam their students say it doesn't matter in order to take money from the students. If you watch sports competitions where there are no categories and where you see lighter opponents defeat heavier ones, you must know that they fight according to the rules, even if there are few rules, there are still rules, on the street you cannot catch someone in a clinch and wait for the end of the round if you are good at wrestling or bjj, there is no referee and one blow can be fatal, on the street you have to be very fast and know a lot in order to defend yourself against a taller and heavier opponent, because street fights last a few seconds, you don't have time for tactics and to buy points for procrastination. Basically, if you have a lot of fighting experience and knowledge, you can defend yourself against a taller and heavier opponent, but it's a difficult task and requires a lot of training and dedication, and it's also too difficult, so size matters.