I started in college just decided to take a course and I was hooked. I now use Wai Lana DVD's and if you're really interested go to
www.wailana.com and get her beginners dvd set. You can also youtube her and see some of her stuff to see if you would like her, not only is she really good on Dvd in terms of explaining poses, she's also very calming she does it outdoors with fantastic views and the music is awesome.
I've been doing her yoga dvds for about an hour a day, one dvd is about 30 minutes in lenght, and been doing it for about 2 months now and my body has changed a lot in that I'm a lot leaner and have lost quite a few inches, I'm also not stressed out and actually very relaxed from the yoga.
Good luck and keep us updated about if you start your yoga journey.
Spiritlite