I'll settle for the Breakthrough Starshot mission. Best-case scenario is that it launches in 20 years and takes 20 years to get there -- and living another 40 years is not impossible.
You'd have to wait another 4 years for them to let us know that they successfully arrived, so it'd be more like 44 years. Doable for the young and healthy among us.
But what might not be quite as doable is inventing/constructing propulsion systems capable of safely attaining 15%-20% the speed of light within 20 years. New Horizons hit 58,536 km/h, but it would've taken 78,000 years to reach Alpha Centauri. The Helios probes hold the record at 252,792 km/h. Cranking that up to 216,000,000 km/h (20% the speed of light) might take some doing and perhaps more time than the project bargained for.