Is it normal for my cat to get aggressive?
Okay, so, my cat is generally a sweet cat. But I
guess she is jealous(?), and if another cat/kitten
is around she becomes extremely aggressive. She
will even attack me, and they are severe attacks. She
will stay aggressive like that for quite a while,
and sometimes I even need to shut her up in a room
alone for a few hours. Is that normal?
Your cat's behavior is not exactly normal. However, it certainly isn't abnormal either.
Most cats are territorial and solitary. Although there are exceptions, most cats hiss, bristle, or otherwise react in a negative fashion at the sight of another, unfamiliar cat. This is completely normal.
Some cats take it a step further. They become extremely agitated when presented with another cat. In this situation, a syndrome known as redirected aggression may occur, and that's what I think is happening in your cat. She gets so worked up at the sight of another cat that she releases her anger on anybody who is unfortunate enough to be nearby.
People are subject to redirected aggression as well. If someone has a bad day at the office and then is short-tempered and angry with his or her kids when he or she gets home, that person is exhibiting redirected aggression.
In both cases, redirected aggression is not abnormal. But it is not a good thing either. Cat attacks can cause serious bodily harm, so you must take steps to ensure that you are not injured.
The simplest way to do this is to prevent contact with other cats. Keep your cat indoors, and don't allow any other cats in the house.
If that is impossible, then I recommend that you continue your practice of giving your cat a "time out" in a room where she can cool off by herself without hurting anybody. However, be careful -- when she is worked up, your cat may attack you before you can isolate her in the room!