I-130 / I-485 for a child, interview

[Treo]

Hi,

I am considered a stepchild, under the age of 21 of an US Citizen.
I have filed a I-130, I-485, EAD and a I-512 travel document which also proves my status of parol for up to one year (august 20, 2003). All documents where filed late June 2002, travel document was rushed within 4 days. Fingerprints are done, EAD was issued, both in September.
Today I got my I-485 interview notice, interview scheduled for late March 2003.

And now my questions. What kind of questions will be asked at this interview? I found a lot about the marriage questions, but they don't apply to me. I am in the US for educational reasons and live with my parents (Stepfather US Citizen, Mother Alien Resident).
My second question would be, after my interview, what other steps are in between to finally get my greencard? Will it be issued the same day or how long (approximately) will I have to wait?

Thanks, Treo