Hi Kathleen,
I've been doing pilates every week for a year now and I really enjoy it. It's mainly floor based so once you're down you're pretty much there for the entire hour. My RA has been manageable so I'm able to do most thing, there's hardly any weight bearing on your joints but if my joints are stiff I give it a miss as some moves require fast movement like straightening alternate legs whilst on your back in a curl up position. I have a really good teacher so that's important but as it's always said, know your limits and listen to your body.
I also do yoga once a week which I also love.
Give it a try, and then you'll know whether it's for you or not.
X