What should I learn if I want to learn a self-defense skill at the age of twenty?

I also studied Taekwondo and Karate when I was a child, but physical education class studied boxing for two semesters in high school, and then went to the martial arts school to learn Sanda. Finally, I think Sanda is very practical, such as Taekwondo and Karate, which have many fancy styles and are suitable for performance. In actual combat, it is generally not necessary to fly first and then kick, and then kick together. After all, actual combat is street fighting, which is different from fighting tigers. As for boxing, most of them only practice boxing, ignoring the attacks of other parts of the body. Moreover, Sanda is comprehensive and has many skills in boxing, knee and elbow. It is recommended to learn Sanda.