I was adopted at 6 months old. Born in Queens City General Hospital on January 4 1973.
I spent my first 18 months with my adopted parents in Irvington New Jersey, then moved to Piscataway New Jersey where I resided until I graduated High School. The only thing I know is that my adoption was closed and that my parents paid a lawyer well to "handle" everything. Can I still find my birth mother? Or is it pretty much impossible?

Why do you wish to find them ? Have you discussed this with your adopted parents ?

Closed adoptions are hard.
I'm not sure if it was Montel, Oprah or Maury but I remember one of them talking about a
.org website that registers adopted children and biological parents. If and when they find the other party they will let you know as long as they give their permission when they are found.

I was adopted at 6 months old. Born in Queens City General Hospital on January 4 1973.
I spent my first 18 months with my adopted parents in Irvington New Jersey, then moved to Piscataway New Jersey where I resided until I graduated High School. The only thing I know is that my adoption was closed and that my parents paid a lawyer well to "handle" everything. Can I still find my birth mother? Or is it pretty much impossible?
Yes you can find your birth mother and/or birth father but it may cost several hundred $s. First, Google adoption registries and get all the info you have on the internet. Second, find a legal intermediary in your locale for details of the process. Remember your first and middle BIRTH NAME may have been changed at time of adoption as well as the date of birth. On the adoption registries you can search for birth parents looking for adoptees so give that a try. Very best of luck in your search.

We have the same situation.. I'm also adopted by my adoptive parents when I was 6 months old and now I'm 21 I want to see my biological parents.. and also like you they don't know any documents and pictures, so its so hard for me to find them... but I'm so curious to really find them and where did I get my features and my medical history...