You are cool!

You have measured out half a mole of water successfully,

i.e. 3.01 X 10²³ water molecules.
One brown rabbit will be added to your garden.

Explanation:
Weighing 3.01 X 1023 molecules of water means weighing half a mole of water. To get the mass of half a mole of water, take the mass of one mole of water (molar mass), 18 g, and divide by two. That gives you 9 g.