Teaching English abroad is an incredible way to see parts of the world and make new friends. You could do this while you decide what you really want to do. Would also look good on a resume.
I think it is definitely a good idea to get certified, but I don't know what the opportunities are like if you don't.
I had a friend that went to Japan. She ended up living there. I researched it 2 years ago. Unfortunately circumstances made it impossible for me.