As a two time homeowner, and a Realtor, I can tell you that the age of the house doesn't necesssarily mean anything. New or old, homes ALWAYS come with some sort of maintenance issues along the way. That's the nature of homeownership.
For example, my first home was brand new. I watched it being built in 1983. In the first 5 years, I had to replace the ceiling in my kitchen after the tub drained right into the crawl area between the two levels (the main drain was not hooked up properly), needed to replace all the windows, fix a roof leak, and even replace the main water main when it ruptured in my front lawn. My current home was built in 1972 and I bought it in 1996. I have slowly upgraded everything, and the house is in better shape at 39 years old then my "new" house ever was.
What do you consider "real old". Metuchen, for example, has homes built in the late 1800's and early 1900's and they are still standing, doing well and selling. Many "older" homes have been upgraded/renovated and are as good as a new home. When you purchase a home, you will have a home inspection performed, and that should alert you to most issues that need immediate attention before you move in (and the sellers responsibility). After that, no matter what you do or what you buy, there will always be something that needs to be replaced/repaired. If you aren't willing to do that, you are better off not owning a home, NEW OR OLD.
Just to clarify, Edison IS only one school district, and has only two high schools. The unofficial differentiation between North and South Edison as far as high schools comes from the NJ School Report card where J. P. Stevens High School performs better compared to Edison High School.
That being said, I am a resident of the town since 1983, and very well knowledgable about the town. However, don't limit yourself just to just North Edison. There are many great values in the "south side", as well as in some other towns depending on why you chose Edison (schools, access to NYC, etc).
Give me a call or email me and I will be happy to help determine your needs and steer you in the right direction, along with educating you on the home buying process.