It doesn't take that long, from an astronomical perspective, or even a geological perspective, to go from knapping stone blades to moving individual atoms using scanning tunnelling electron microscopes. Supernovae just don't happen often enough to keep civilizations from reaching advanced states. The main constraint for us is distance -- we don't yet have the technology for interstellar flight (interplanetary flight is possible but not practical); once that hurdle is behind, the next constraint is each other. We'll probably find a hair-trigger hostility just waiting for us to try our first steps.
“We’ll probably find a hair-trigger hostility just waiting for us to try our first steps.”
We already have, and it was triggered from going no farther than the moon.