Hello there,
NJ public school systems vary considerably around the state. Each school district has its own way of doing things. Newark school district is one of the largest in the entire state. You will be assigned a high school based on where you live. Newark has several of its own magnet high schools. Now the Newark school system is not known for being the best. So if you do attend, you might consider supplementing with other material.
Several NJ counties also have their own magnet system. Bergen academies is one of the most well known. But there are others as well: Ronald McNair, High Technology High, Union County, Biotechnology High). Each has their own admissions standards. Not sure if they accept transfers or not. But look and see.
When applying to college, you’ll be compared to other kids from your high school. While going to the top ranked magnet might seem like a good idea, keep in mind that you’ll face stiff competition. So going to a lesser known public school system like Newark might not be a bad idea. But just make sure that you study hard so that you can do well on the standardized tests.
NJ also has some of the best private schools in the country. Whatever you choose, best of luck!