Annie, there are tons of yoga videos on youtube, so you can try it without spending money or going out to classes.
Here is a gentle set of stretches that keep you on the floor - nice for folks with balance issues.

http://www.youtube.com/wa...A7G3hZbg&feature=related

When I do sets of movements I will sometimes hold a position for a long time breathing out any tension that comes up and not necessarily move through them this quickly.
First and foremost though is to try it, get a feel for what your body says in response and then go from there. Breath and calm mind are as important as body movement with yoga.

If and when you choose to do some stand up and bending stretches the basic Sun Salutation series of movement is one of my favorites. Again, I take a long time doing it, holding each position for as long as I feel a need to. Some people move through it quickly, some not...your choice.