Usually the good medicinal reishi have a shiny red to them, this one appears to be a different species of ganoderma. Chances are this one doesn't have any medicinal properties or way less medicinal properties than the true reishi. Here's what medicinal reishi look like. I probably wouldn't bother harvesting this one, just keep an eye out for the more shiny red ones.

I also grew some at home from a kit and they ended up looking like antlers