"However, there’s hope. Say, for instance, that we were able to develop the technology to travel at light speed–not only would it be amazingly badass, but it would allow us to reach plant in a mere 20 years (roughly how long it takes a human to become educated…space school, anyone?)."
Time does not work that way.
If you travelled at light speed from here to Gliese, do you know how much time would have passed for those who were looking forward to 20 years of space school? 0 seconds! This how how we can detect muons in mines many km under the surface, and is the basis of the twin paradox.
Also, "has the potential to be warm and wet enough to nurture Earth-like life" =/= "can support life."