I've jumped out of 13 perfectly good airplanes I might add. Speaking from experience, it's not to be of concern. These were all done prior to me having top surgery as well.
If you've never skydived before, you're going to be on a tandem jump, aka, attached to someone who knows what they're doing. You're just along for the ride. Also, very unlikely that the opening shock would cause enough force to do any damage such as broken ribs.