You will not be rejected for membership based on your credit scores. The above posters are correct in that your son will need to join first and then when he has his account information (savings/checking) you will be able to join through his membership.
NFCU is the best when it comes to working with them. Once you have joined you can always speak with one of their customer service reps who will be able to help you determine what scores might qualify you for what products. If nothing else an application for one of their cards can be referred for a secured card. And they do graduate their secured to unsecured with proven history on the account. They are also known for granting incredible credit lines for lower scores once you have an established relationship with them.
I am NFCU's #1 cheerleader. They are my primary credit resource and have always been easy and fair to work with.
