Hi Wendy, and welcome
This is a great forum (and website in general), as I'm sure you've already found.
As others have said, the D FA100 Macro WR is an outstanding lens. Reviews and technical data aside, you have to try it to believe it. Just be aware that, as a macro lens, it has a long focus throw and some people consider it a little temperamental in the way it can rack back and forth (and not *that* quickly) when focusing. So long as you understand this, I'm not sure there could be a better choice for macro. And as Des has informed you, there are related options that may fit your requirements for less outlay. The basic design, though, is superb.
As a final comment, I would say that the lens is far more important than the camera body in most situations. I used to shoot with a K5 then upgraded some time ago to the K3. While the K3 is capable of better resolution, I *often* find myself using the K5 so I don't have to switch out lenses on the K3. At normal magnification and viewing distances, no-one would really be able to tell which camera body I'd used. So, the investment in a good lens or two is - generally speaking - wiser than investing in a better body alone.