Yes it is possible. From your bare stat’s, you are in the ballpark. Are your chances good, no, but not any different from all the unhooked applicants that are successful. The decision will be driven by human judgment of how you fit what Harvard wants which is determined by your LoR’s, essays, recognition/awards, quality of EC’s and perhaps your interview. The vast majority of S’s friends at Y don’t have international or national recognition. They all did very well in school and on their tests. They all seem to have had meaningful accomplishments in non academic areas such as music, sports, community service, writing, debate, etc… His two friends from town who got into H were the same.