High school electives

Im a sophomore in high school, and so far ive been doing fairly well in my core classes, meaning history, english, math, and sciences. In most core classes so far ive been around the A-/B+ range. Although, I was informed that electives did not really matter and were just ways to keep you busy, so I completely disregarded electives all throughout my high school career. These electives include band, P.E., art, things like that. Ive passed most of my electives with a C, but there were some that i really did not care about and failed. This was all fine until i heard that your GPA accounts for all classes, including electives, which would mean my GPA would be brought down by quite alot. So my question is, how important are high school electives for getting into college? Do they actually count toward your GPA?