Interview was easy.. asked us how we met and where.. if we had ever been married e.t.c.. in our case there was some weight on that since my fiancé has a daughter from previous relationship so i guess they wanted to be sure that we were telling the truth about not beeing married before or that the child is actually mine... so if ur in a similar situation bring also the birth certificate of the child where it says the fathers/mothers name a.s.o.. it helps to keep immigrations happy
also it was just basic questions that where easy.. as long as u answer honestly and have everything ready.. everything from the checklist that is that they demand u have with u to the interview its no biggie and u will soon be together with ur baby !