Used to do that and karate back in middle school, I got some weird embarrassing photos of me back in the days. My dad was always a fan of martial arts. Get ready for a lot of cardio and flexibility training.
It's better than nothing and you might f*ck up the avg untrained guy, provided there's not too much of a difference in weight or height, but you're wasting your time sxb. Join a Muay Thai or an MMA gym if you want to actually learn practical skills.