9/11 terrorist attacks — four months before she was born.“Whenever there’s an important event in my life, I can just look up at the sun or feel it on my skin and know that he’s with me,” Alexa told The Post. The native Long Islander details the enduring effects of her loss in the new Magnolia Network and Discovery+ documentary “Rebuilding Hope: The Children of 9/11,” out Tuesday. The doc focuses on Alexa and three other young adults — Ronald Milam Jr., Gabriel “Gabi” Jacobs Dick and Jamie