You are only 15, it is normal to feel angry. But how you mature
and grow up in life would depend on how you laugh off this incident
and just forget about it. Its a one-off incident. Its not as if
those two guys continually bully you and you have no choice but to
stand up against them. Just forget about it.
Even if you reported this to the teacher, you would have made
yourself infamous in front of your schoolmates, and two more new
enemies of those two guys.
You must know when to stand up for yourself and know when is
best to stand down. This incident is best forgotten.
Trust me, there are more battles for you to make as you grow.
Especially when you go out there and work in the office, where's
there is a lot of backbiting, backstabbing and office politics.
Save your energy and wise up.
it is not a matter of age, 15 or 51 also must protect oneself
against unjust people, at 15yo, you protect yourself, by 51, you
may need to protect your family, parents, ah ma and ah gong...so it
is good that at 15yo, he start to train up.