PHILADELPHIA -- A once-homeless Philadelphia teen, nicknamed "Harvard" by bullies for being a bookworm, is now heading to Harvard on a full scholarship."I wanted to work to make things happen," Richard Jenkins said. The 18-year-old reflected on his life with his mother and two younger brothers.He was homeless for years, living in shelters in Tennessee and Florida before landing in a Germantown shelter back in Philadelphia, where he was born.He will graduate from Philadelphia's Girard College next month as the class valedictorian, enrolling at the Ivy League's Harvard University for the fall on a full scholarship. He decided to focus on academics while concealing the fact he was living in a homeless shelter."There were times when we would put the food we'd already started eating back in the refrigerator because we knew there would be no food coming later on," Jenkins added.He told ABC7's sister station WPVI-TV that he plans to study computer science with a concentration in the growing field of artificial intelligence.He said he owes much to teachers and friends who had faith in him, and to his family whom he wants to be able to get out of its financial despair."My mom was a great source of inspiration, because she was doing all she could to keep a roof over three boys' heads," Jenkins said.What advice does Jenkins have for young people struggling to overcome humble circumstances similar to his?"My advice is to stay focused, that's the only advice I can tell you," he said.Graduation day at Girard College is June 7.After graduation, Jenkins will head to Harvard University in Cambridge, Massachusetts, just as focused and inspired as ever to achieve his soaring goals and aspirations.A GoFundMe account has been set up to help Richard with expenses not covered by financial aid.