I've had sex with 4 men, is that too much for an 18 year old?

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 and
passing the info around?
Four sexual partners at 18? That's waaaay too
much! My opinion. What do you guys think?