Size does matter, but there ARE specific, concrete things you can do to make up for being smaller. With the right techniques and strategies it’s absolutely possible to successfully hold your own against bigger, stronger opponents. And with the right leverage-based techniques, you can even go on the offensive and bring the fight to them!
Whether you’re male or female, if you have problems against larger opponents then check out https://www.grapplearts.com/defeat-bigger-stronger-opponent-series/