Steve IS on my birth certificate. I want his name off of it as "Chris" is my biological father per the paternity test.
Yes, we get that.

It does not change the legal reality, which is that it is - BY LAW - too late to contest Steve's paternity. The ONLY way to have Chris put on your birth certificate is through adult adoption (if it's even available in your state), and you cannot be adopted by Chris unless you sever LEGAL ties with both Steve AND your Mom. You cannot sever legal ties with only one of your legal parents, it has to be both.

Understand that if you sever legal ties with your parents via adult adoption, you are not entitled to receive any of their estate when they die, unless they specifically will it to you by name. That means if they die without a will, you get nothing and you don't have standing to petition the court to inherit. If you sever legal ties with your parents so Chris can be on your birth certificate and your Mom falls seriously ill, you will NOT have standing to visit her in the hospital. If she dies, you will not be notified as next of kin, because you won't be kin any more. Undertaking an adult adoption will render you a legal stranger to your Mom.

Do you understand the seriousness of this idea?

By all means, have a relationship with Chris. Change your last name to his if you want. But understand that having him on your birth certificate has some serious consequences for you that may not seem like a big deal now, but will be devastating as your Mom ages and eventually passes.

Having a hissy fit and squawking at the volunteers because you don't like the legally correct information you were given doesn't change the legal correctness of those answers. Feel free to pay an attorney to be told the same things we just told you. It's your money.