I think we are like mold on a tomato that is floating in space.

At the moment, we are barely visible. But over time, the whole tomato (planet earth) will turn into mold.

Earth is 10^24 kg.

So far, humans are something like 10^11 kg.

Maybe 10^13 or 10^14 kg if we count all our stuff, like roads and buildings etc?

So we still have about 99.9999999% of "colonizing earth" in front of us.