We don't know what the Great Filter is, but it must be pretty destructive for a civ. I just want to point out the fact that the Great Filter is probably still ahead of us and that we shouldn't take our existence for granted.
If there is a great filter...
I mean, as you said, we're pretty early to the scene. Why can't we be the first in this galaxy? Perhaps planets like earth aren't rare over the lifetime of a galaxy, but they are rare in these early years of a galaxy. In other words, earth just developed quickly, so now we're here before any other earth-like planets have had a chance to develop intelligent life.