My 6 Year Old Daughter (kindergarten) Got In Trouble Today

My 6 year old daughter (kindergarten) got in trouble today for touching a boy's private parts. She didn't deny she did it, but she had no reason for doing it. I assume it was pure curiosity, she has learned that boys have different private parts than girls and seems somewhat curious about this at times. I am just wondering how I handle this and how do I know this is something more than just a child's curiosity? My initial reaction was pure anger. I ended up making her cry and used words like "disgusting" and "horrible". I now regret some of my words and in my attempt to convey the seriousness of the situation and make sure she understands that it is never okay to touch somebody in that area, I may have gone too far and was too harsh. I am just looking for some reassurance that her behavior isn't completely abnormal (or maybe it is) and also some advice as to how to handle this with her so that she understands this behavior is not okay without making her feel so ashamed that it makes her think all curiosity is shameful.