President Joe Biden is already starting to counter former President Donald Trump’s attacks on his age by addressing the issue head-on before their inevitable rematch after their respective primaries. In the Biden campaign’s first major ad buy of the general election season they tackled the criticism about the president’s age through humor, directness, and tying it to his experience. “Look, I’m not a young guy. That’s no secret,” Biden said in a direct-to-camera video before highlighting his administration’s legislative accomplishments, such as passing an infrastructure bill and improving the s…