The realistic estimate, is possibly never, unless/until we learn something that we do not know yet, about how to exceed the speed of light, or travel without moving across the intervening distance.
But since we don’t know if/when we’ll make such a discovery, we can’t estimate when or if we will actually make such a discovery, let alone when that would lead to whatever potential technology we don’t know about yet.
There are a few ideas. For example, the Alcubierre Warp Drive idea. But it has many unknown-if-they-are-solvable problems. Such as, it would seem to take more energy than exists in the known universe, to get it to work. Minor delays expected.
(And that’s optimistically assuming we don’t eliminate ourselves with global climate change, and/or simply by causing life as we know it to cease living due to all the things industry and agriculture and land use etc do that are driving species to extinction, wiping out the ecosystems that we too need to live.)