Do we have the knowledge, technology and resources to colonize it?
Simply put, no.
First off, you need to forget about knowledge, technology and resources and look to biology, sociology, and psychology. How many people would be needed to create a self-sufficient modern colony? The number is rather large. It's not 100 people, or even 1,000. It's at least 14,000 per Cameron Smith, "Estimation of a genetically viable population for multigenerational interstellar voyaging: Review and data for project Hyperion." Acta Astronautica 97:16-29 (2014), and that's risking extinction. Sending 40,000 people is a better bet.
We can't do that. Not even close.
Suppose we knew how to put people in what science fiction authors call "cold sleep." We can't do that, not even close. In that case, we don't need 40,000 colonists. We just need 40,000 embryos, plus 4,000 or so young women in cold sleep who will need to get very busy getting busy birthing implanted embryos upon waking up.
What about the target planet? We would have to terraform it if the target planet doesn't contain a breathable atmosphere. We can't do that, not even close. The closest we can do with current technology is to do what we've done on Earth, which is to try to de-terraform it. On the other hand, if the target planet does contain a breathable atmosphere, that would most likely mean bacteria and viruses that would greet the colonists with a hearty "Yum!" The colonists would have no defense. Either way, this is a showstopper.
Ignoring that, can we send a spaceship containing a few thousand young women in cold sleep plus 40,000 embryos in cold sleep to a habitable planet 20 light years away? Those colonists need to eat. They need to eat quite a bit since each colonist needs to eat for two for twenty years straight. We need to send a self-sustaining food source. We can't do that, not even close. Every attempt to make a completely closed, self-sustaining ecological system has failed -- and that's right here on Earth. If we could do that, we would need to send a lot, lot more than 4,000 women and 40,000 embryos.
Even with the reduction from 40,000 people to 4,000 women, this spaceship is still extremely large. We need to send animals, plants, farm equipment, materials to make dirt, mining equipment, manufacturing equipment. This thing is several orders of magnitude larger than the International Space Station. Scaling things by an order of magnitude is hard. Scaling by several orders of magnitude--we can't do that, not even close.
Suppose we can get the spacecraft to 1/1000th the speed of light after exiting the solar system. That's about twenty times faster than the current velocity of the Voyager spacecraft, and those are tiny. Getting something the size of hundreds of space stations to that speed is once again a we can't do that kind of proposition. Scaling up by a factor of 100 to 1/10th the speed of light is science fiction. Even at that speed, it will take 200 years to reach the target star. We need equipment that will remain reliable and viable for centuries. This is yet again a we can't do that kind of proposition.