Is A Esl Teacher A Good Career To Have In Seoul, South Korea? ?

Hello, Do you guys think that it will be a good idea to open my own English Academy in Seoul, South Korea? I am from America and would love to be a ESL teacher for young children. Does this job make a lot of money per month? What is the yearly salary? (please provide an estimate regarding if can support me enough) Also much money would I be making is US Dollars and also the South Korean Won? Would you all recommend that I open up my own academy or should I apply to work at one? Is there any helpful knowledge that you could pass on? I would also like to know what i should major in if I would like to be an ESL teacher, and also which top American Universities I should look into? For example, Stanford, Harvard, Duke, UPenn, etc. Any money smart tips that you could share? Also, should I get a part time job also while I am a ESL teacher or no? Thank you all for your help!