text: As long as you graduate and meet all the requirements in terms of number of credits and GPA, you're considered to have completed the high school curriculum and should be considered equal to any students a year older than you.  Colleges are not heavily influenced by extra-curricular activities except when it comes to scholarships.  It shouldn't affect your admission to the school.  It could be a negative point against you if you have only three years of an activity instead of four, but you can compensate for that by looking for other volunteer activities, or taking on positions of responsibility (be the UN Secretary-General instead of the representative from Lesotho... or whatever).