How much sex is too much?

Im a 16 year old girl and I've been with 7 guys, almost all of them being older. Although the amount of people I sleep with dosent bother me, some people close to me seem a little shocked when I tell them I've been with 7 men. I always use protection and make sure they're clean and get tested regularly. I'm on birth control and have been for almost a year and a half now. Mostly my question is for the older women on this site, is it bad to sleep with this many men? And is it abnormal or unsafe? What's the average amount of men woman usually sleep with?