. >> news4's barbara harrison intruces us to the 16-year-old who is now paying it forwarhi >> reporter:was three years ago, not long after 13-year-old meg gallagher was diagnosed with leukemia. >> i heard someone sd leukemia but i didn't know what that meant. >> she had been not feeling well for a couple weeks. she was a te-ager, i thought she was making it to get out of school. >> reporter: but it turned out to be very serious. >> they were able to tell under the microscope she hadke la cells in her blood. >> i remember it was scary and i remember why was i on the floor with people with cancer. i saw w people whoe bold. >> her mom explained what was happening. >> she was trying in the shower. i told her to st. i didn't want anybody to cry. >> meg told her mother she wanted to turn that difficult holiday memory into something positive, collecting toys and gifts for kids here at the kildren's hospital where meg had spent so mas recovering. she started meg's very merry ve gick while she was still a patient. her cart these days is overflowing with gifts ofll ages. her favorite on this ct