I grinded with another guy..?

Ok...Well I was at this weekend camp and in the evenings there were club parties up until about midnight. I have a boyfriend and we are great together and I wouldn't swap him for the world but when i was dancing this guy started dancing on me and we ended up grinding...by the way I am only 13...do you think i should just pass but I feel guilty, we didn't kiss or anything so I guess it was just for abit of fun but what should I do...forget about it? THANKS <3