The more time you can give yourself, the better when it comes to Northridge. Essentially, you would do well to start putting out some feelers as soon as you realize that you'll be relocating to the area.
With prices and competition the way they are in Northridge, you need to make sure that you have the strongest application possible. If you don't have a strong rental history or income, be aware that you will likely need to find an apartment that will allow you to put a consignor on the lease in order to get your apartment.
If you're attending the University in Northridge, nearby bus stops can provide easy access to the rest of the city. However, Northridge is part of the greater L.A. freeway system, which means if you want true mobility you're going to want to get a car at some point.
Northridge is just a short trip away from the rest of Los Angeles, and that's a city where entertainment is king. With the best music scene in the US, and museums like the Getty that people travel across the world to see, you can spend years exploring L.A. and not take in everything the city has to offer. Take a surf lesson to appreciate how great living in California truly is.