I've Had Sex With Only 4 Men & I'm 18yrs Old: Is It Too Much?

This is kind of funny thou. There are some 15 years old girls in secondary school who's had it with well over 10 different guys, but they cannot be categorized among decent girls. Now, this girl is in a university and just 18 but has had it with four different guys. She told one of her girlfriends and the story leaked.

She is bitter that her friends are calling her an "ashi". See her story below:

I am 18 years old and in my second year in a private university. I started having sex when I turned 16 after leaving secondary school and I have had four sexual partners so far. I dated 2 of the boys while the other 2 were just flings.

Recently I confided in a friend the number of men I've been with and I later saw text exchanges between her and another mutual friend of ours laughing at me and criticizing me. They called me all sorts of names including wayward and loose. 

I've been with only four men, is that too much for a girl my age? I thought it was the norm so why are my friends condemning me?