Listing activities on common app

Hi! I am currently filling out the activities section of the common app. I have participated in theatre for all four years of HS, but during my junior year became the president of the program. I am listing this leadership position and participation in theatre as one activity; but when it comes to the “participation grade levels,” I don’t want to be misleading by choosing 9/10/11/12th grades, since I obviously wasn’t the president as a freshman. I also don’t want to only select 11/12th, because it will seem like I only began theatre in junior year. I might be overthinking this, but please let me know what the best approach for this is. Thank you!!!