I am a Taekwondo student (Green one belt). I've given my lessons a pause due to studies. I say go for it only if you are COMPLETELY sure you want to learn martial arts. This style (Taekwondo) is mostly based on block-and-kick attacks and aerial kick attacks. I reckon its better than Karate. Go for it if you think you can stand it. In my batch, there were many students who used to complain about too much sunshine and other idiocies. Don't bother if you're like that! Also, I'd say if you can find an instructor, you should learn Ninjutsu instead. But as that requires total devotion, this is better. That's my advice.
Also, you might find the White to Yellow belt syllabus to be a comlete laugh. Just don't quit and wait till you gain more experience.