There are many obstructions that make it difficult to imagine a future in which humans inhabit exoplanets.
Human technology will have to advance to a considerable extent before even just travel beyond the furthest planet of our own Solar System can be considered. For the direction of these advances, visit our Future Goals page.
Even without these advances, though, humans may still reach Mars within our current lifetimes, allowing access to a sort of proving grounds for a shocking prospect: human civilization beyond Earth.
Whether or not humans are able to transcend the bonds of the Solar System and colonize exoplanets is up to the how much work we put into achieving this goal. In any case, the future holds infinite possibilities, and our expansion into the stars seems inevitable.