Adjustment of Status - I-485

Hi all

so on march 20th we had our marriage based (c9 category f1 to AOS) is done and here is our experience.

we went in around 30 min before appointment and within 35 min after appointment time IO called us. She was white but had Russian or European accent.
she ask so many question based on forms. she made a mistake first by clicking on button in her computer that our interview is finished lol, she said "oh god, i by mistake finished your interview even before i started it" lol
then she ask following,
what is your wife's name
father & mother-in-law names
what we did on last birthday,
if we have any other documents for her?
she confirmed where do we live now and previous addresses.
she went though with photo album.
she asked she we have met or seen each other family.
how we met?
when we start dating, anniversary dates, marriage date and place.
to me (non citizen) she ask about my F1 & J1 visa , like when i came here and all.
she ask where do we work now and previously.
i have a step son , she ask me his date of birth and name
she ask about my unauthorized work during my F1 visa and after being out of status as well. (as i disclosed everything in my aos application)
and last she ask me all those yes no questions

and sometime she ask me some questions 2 times like my step son's DoB and name..

so now here is one problem happened during interview, she ask my wife about extra documents and my wife said that we have insurance (medical) together now and just after that she ask if we have joint car insurance and my wife said no as we don't have car yet, then she said how we get to detroit then and i said we have rental car and she ask my wife whose name is car on and by mistake my wife said" mine" but actually car was on my name not on my wife because my wife dont have driver's license as she do not know how to drive.

IO ask my wife why she said car is rented on her name and my wife said she is nervous and got confused with car and medical insurance term..

accept that we answer everything very well. then IO ask me for my EAD and SSN and made copies of extra documents we provided to her. then she explain about 2 year conditional thing and she said " you will get decision in mail if it gets approved"

i am worried a little bit why the hell she say "if its get approve"

if anyone had same experience please do let me know if using of such terms are common by IO or not.

thanks everyone and i hope my experience may help to other