There's no doubt about it. I'm small. I stand 5'4" tall and weigh about 130 lbs. With the martial arts being a male-dominated realm, I've had to deal with numerous difficulties related to my lack of height, weight, strength, and reach. While there have been times when this has frustrated me, in the long run, these disadvantages have benefited me in ways that were not readily apparent at the time.
Performing martial arts techniques and manoeuvres as a smaller individual is like playing chess without a queen. Your opponent has the upper hand and you have to use the pieces that you do have to the best advantage. Many beginner players mentally give up once they lose their queen, seeing it as futile to continue. But players who get used to playing without a queen, improve their overall strategy in the long run, learning to use their pawns and other pieces to keep their opponent on their toes. And the pawns, often seen as nothing but fodder, can even become queens through superior strategy. The same is true for the martial arts. At first, you may be frustrated by the uphill battle of trying to make techniques work on larger people. But after time, you'll adapt and improve, using good technique, speed, reflexes, accuracy, etc. to bridge the size advantage gap.
That being said, there is less room for error when you play without a queen. The more pieces you lose, the less flexibility you have to check mate your opponent. In applying this analogy to a martial arts context, imagine yourself being attacked on the street. People who attack others usually do so when they perceive that they have the upper hand. The attacker may be a larger man attacking a small woman. He or she may be wielding a weapon of some sorts. Or they may be attacking with a group of people. With the odds stacked against you, you can't afford to make mistakes. Every blow you take may be the one that takes you out, so you have to try and make it so that every technique you do cuts your attacker down a notch. Every successful blow you get in evens the playing ground and makes your attacker(s) re-evaluate whether or not you're worth it the risk.
Being small means that I continually find new challenges as I add to my knowledge of the martial arts. Even now, with a 3rd degree black belt in Jiu-jitsu and over 14 years of training, as well as having studied a variety of other martial arts, I still come across new techniques or new training partners that require that I modify or compensate in some way for my lack of size. The difference is that I now know that by overcoming these additional challenges I have more opportunity to improve my technique than my larger, stronger colleagues.
Check and mate.