You have to learn to crawl before you can run. The patience, humility and wisdom we will need to keep ourselves and the earth healthy are exactly the skills we will need to terraform other planets. Also an Earth not stressed by our arrogance, greed and stupidity will be more likely to provide us with the resources necessary to begin the process of terraforming other worlds. We have been blessed with two classic cases of failed worlds habitats, mars and venus. They could be valuable learning tools. They are likely the types of worlds we will meet out among the stars. We are going to have to build new homes out of what we find when sending starships out there. I suspect if we did find an alien ecosystem out there it would be a death trap for us. It took billions of years of evolution for us to evolve the capacity to live among the allergens, protiens, plasmids, viruses, pathogens, and toxins saturating this worlds soil, water and air and not die. Can you imagine what would happen to our bodies when exposed to a planet representing billions of years of separate viciously competitive biological evolution? Brrrr! And no I don't think advanced medicine would solve the problem unless we decided to give up our humanity.
Maybe after we terraform the red planet. Because Mars is easier to terraform, we already have the tech to hear it up (we don't have the tech to cool down Venus) and it will give us time to learn if we can terraform Venus.
Venus is at the edge of the habitable zone, we are not a hundred percent sure if it is in the habitable zone or not. There are some that believe it is and some that believe it's not.
It is much too early for mankind to even begin considering whether to try to terraform Venus or any other planet for that matter. We have our own planet which we started with a well balanced ecological system and we have managed to severely threaten it in only a few short generations. Let's practice on fixing our current planet and then we can start to think about starting with a new one.
While it is an interesting idea the terraforming of Venus would not be cost effective as the requirements to enable men to inhabit Venus would be too costly for a group to pay. It would be better to look at terraforming Mars which is not as hostile to life as Venus.