I don't see how teaching english in another country is a waste of time.
1) You'll have a job
2) You'll be able to experience living on your own...in another country for that matter
3) You'll gain experience teaching english to those who don't have it as a first language, which will be difficult, yet rewarding.
I don't see anything wasteful about the idea. The only thing you should consider is your motivation to return to school, as others have mentioned, if you really wish to return to school afterwards. I'm a master's student currently, totally looking forward to finishing my thesis and getting a full-time job, using the knowledge I have gained and using it in the real world. I plan to do a Ph. D program in the future, but I have been in school my whole life and want other experiences other than school while I am young.
I say...if you want to do it, do it. Don't NOT do it, just because someone else says not to, otherwise you'll regret it later.