Practical use of Taekwondo?

E was getting on to N’s nerves. Both were fighting over the little red rocking chair. Without hesitation, N raised her leg and aimed at E’s shoulder. The kick pushed E back by a few steps and it certainly brought big tear drops to E. Instantly, N knew she did something very wrong which would warrant the use of the cane. She quickly went over to E and rubbed his shoulder while apologizing to him. Meanwhile, E was thundering away. L

I had no choice but to bring the cane out to discipline N. It hurt me more than what the cane did to N. It left a red mark on her thigh but thank god, it went away the next day. And of course, my poor little boy! Now, I am hesitating if E should pick up Taekwondo too, as a self defence skill or a convenient fighting aid??