Best friend BIGG ARGUEMENT?

So yesterday was the last day of school. Me and my friends went to the park we were playing air tag she tagged me and said I was it actually when I was already it and tagged her before and said no tag backs. She lied and said that I was cheating when she was really was so we was arguing and then we wasnt talking to each other. She also said when it's the last day of school she was gonna act mean. Do you think this is why she did this yesterday ??? Advice please should I say sorry or should she