Go and have a good time
I have found that riding the ones that have the bar that comes down and holds your shoulders is more comfortable than the lap one...but that doesn't mean you cannot ride those (usually the older wooden ones) because they're just as much fun!
Because you are only a few weeks post-op, don't go crazy and ride every one ten times, and it would probably be a good idea to run it by your surgeon, too.
YAY for feeling better