US Representative Joseph P. Kennedy III is preparing to run in this year’s Boston Marathon, his office confirmed Friday. Kennedy is included in a list of registered runners on the Boston Athletic Association’s website. In April last year, Kennedy, 33, took to the US House floor to honor the victims of the 2013 Marathon bombings tragedy. “I think, like many of my colleagues from Massachusetts and like so many people from Massachusetts and from really around the country and around the world, I have always delighted in Marathon Monday,” Kennedy said. “It’s about a community that comes together to cheer on not just the runners but to celebrate what we have built together.” Kennedy’s wife Lauren, 29, is also planning to run.