Certified GKH Gardening Expert
I checked some Michigan weed guides and didn't see it, so I would leave a couple and let them flower. Usually once it flowers, it's much easier to identify. Then you can check some online wildflower guides according to the color of the flower. Weeds are also easier to identify with the flower. Also look around your yard or a neighbor's yard for a tree or plant with that leaf shape that may have dropped seed.