In NJ, to change your name under 18, you have to have both parent's permission (unless only one has legal custody then it's that parent) and they appear in court with you. Once you turn 18, then you can do it on your own and it's pretty easy, but takes 2-3 months to go through everything. (and about $375, but $200 of that you may get waived for low income individuals, the rest is for publishing in the paper twice.) The price is the same regardless of it's before or after your 18.
Gender change is easy, there is a
form on the DMV website that needs to be signed by your HRT doctor or NJ licensed therapist. Also everything needs to match social security which you can do after ID change and a letter from your HRT doctor. In NJ, they don't use Social Security records to match, but your employer will need to use legal name associated with your SS#.
The great thing about NJ is that statewide, it's illegal for someone to discriminate against you for being transgender, so it shouldn't be that big of a deal and NJ is pretty open minded.
