Despite what the world will tell you, you have the right to defend yourself. Jesus commanded his disciples to get a sword even when they were with him. Christians are not second class citizens.Luke 22:36
Then said he unto them, But now, he that hath a purse, let him take it, and likewise his scrip: and he that hath no sword, let him sell his garment, and buy one.
The avenger of blood is spoken of several times in OT law. This is the person that could take revenge on mistreatment of himself or his family when warranted. This is covered for murder in Deuteronomy 19.However, also knowing what God said in Matthew 5, one has to temper themselves. You have a reasonable right to defend yourself if attacked. However, if you're experiencing a situation where someone is calling you a bad name or two, it's best not to stoop to that level. At your age, something like that will become meaningless. Believe me, we've all been there and all had to deal with it at one time or another in one way or another. The best thing to do is to get away from that nonsense because the person that generally does that kind of thing does it because they feel inadequate.Matthew 5:22-24
But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire. Therefore if thou bring thy gift to the altar, and there rememberest that thy brother hath ought against thee; Leave there thy gift before the altar, and go thy way; first be reconciled to thy brother, and then come and offer thy gift.
Raca being an expression of saying something like "You!" in a derogatory manner...similar to saying "Oh, it's you!" as if one is mad at them.