If you have friends outside school. Good enough already.
Infact, my friends who lasted longer are the ones outside
school.
Because, after graduation, we each go our own ways, friendship will
eventually fade.
All my friends in school I no longer contact already.
Only one left, but she was someone I know since Primary
school.
So no worries, as long as you focus on your studies, achieve good
grades so you can further your studies. That is the reason why you
are in school anyway.
Once you graduate to higher education or start in the work force.
You will get to know a lot more other friends.