The signalling is in you being accepted to Harvard. Recall the Ivy Leagues have in place a system that emphasises "holistic admission" instead of the de facto more meritocratic competence indication system of say Caltech. An important part of getting in is having the right extracurricular activities on your resume and often the right activities are the activities that people doing the judging engaged in when young.

Especially avoid anything indicating you might be the wrong kind of white person, when it comes to admission they are discriminated against even more than Asians:

[W]hile most extracurricular activities increase your odds of admission to an elite school, holding a leadership role or winning awards in organizations like high school R.O.T.C., 4-H clubs and Future Farmers of America actually works against your chances.