I will be attending Northeastern, I got into the N.U. in program… irrelevant to the question. But I’m really really stuck with choosing what I want to do. I can’t decide if i want to do business or engineering. I also can’t decide between 1 co-ops and 3 co-ops… I’m really torn and wondering how easy it is to switch these things in university, as well as if anybody was stuck between these two fields and how you chose which path to take
You will have plenty of time to choose your coop pattern, midway through sophomore year at the earliest.
At any university it is easier to switch from engineering to another field, not so easy to switch into engineering due to program structure and required courses.
would it be worth it so go in undeclared or should i choose a major?
My son was in the same boat. Your lucky that NU has both majors. My son basically had to decide between attending a tech school or a business school because he did not want to attend a large monster sized school like NU or UMASS.
Tom is right. Engineering classes are sequenced and full of prerequisites so one is better off starting that track early.
The tricky part comes in when and why you no longer want to do engineering. Schools have created a very horrible situation between the engineering programs and the business programs. Many schools do not adequately allow for the tougher schedule that engineering entails. This causes problems all the time when kids struggle in engineering and the resulting GPA is below what is needed to get into the business school.
You need to inquire about this from NU directly and get the specifics of what is needed and how one corrects a low GPA from engineering. Maybe summer classes or just talking business classes outside the major are enough. They have a path. You just need to inquire what the path is. Worse case is you repeat another year.
Best of luck. If you have the grades to enter NU, then you will be fine.
While doing an internal transfer to say Penn Wharton or NYU Stern may be highly competitive I believe it is fairly easy to do an internal transfer to DMSB at Northeastern providing that you are not on academic probation. Others may have more knowledge of this.
@swainthings northeastern has a combined business/engineering program, 
The undecided program is really good - I would recommend it if you are really unsure. They will make sure you take freshman classes that will work with whatever major you end up with.
While I really like the program as well, for possible engineers, this can cause issues with prereq’s, especially already coming from NU.in, where you’ll likely take more general courses. I would recommend starting with engineering.
Northeastern internal transfers are very easy compared to many other places. In most scenarios, it takes a semester to switch over, and that’s it. Even during that semester you can often enroll in the needed courses during the switch. I had a friend who switched from the College of Science to Business, and the process was really painless. There’as a lot more potential harm in needing an extra semester or year to catch up on engineering prereq’s going the other way.
Don’t forget you can also do 2 co-ops as well. Not sure if it was meant as a range in the OP, but just making sure. As said, it’s easy to switch as needed. If you want to have the opportunity to switch majors after your first co-op, I would try for a Spring co-op (4th semester 1st co-op). If you’d like to have it set more or less before co-op, go Fall (5th semester). After your first co-op, you can reevaluate and decide how many more you want to do.
As you go through all of this, all these details will come second nature to you - it’s a very Northeastern thing to have an incredibly complicated/unique academic plan/path given co-op and all the different directions you can go. It’s fun to look back once the dust has settled.
Good luck 
I would do the business and engineering combined major. Best of both worlds.