Financial talk

My fiance and I are quite young (both soon to be 21), but we've decided that rather than throwing our money away renting - we're going to go right to buying. (Rents around here are just as much, if not more, than a mortgage) Being so young however, we've got questions. My fiance started a new job several months ago, and after his six month mark we're going to go to our bank and see what we can do about getting approved for a mortgage. We both belong to a pretty good bank (sikorsky credit union). After getting pre-approved I assume the next step is to talk to a real estate agent and find a house we like. My fiances mom is a real estate agent, so that wont be too difficult. After finding the house that we like, and making an offer.... how long does it usually take for everything to happen? Does the current home owner have to pay for all the inspections and such? We want to make sure that the house doesnt have any major problems. Any tips are welcome!! Thanks!! I'm asking all these questions because due to our age its possible that people might try to take advantage of us. My fiance is pretty smart on the house buying subject, hes read a lot of books and articles. We just want to do our homework before jumping into anything. So any suggestions/tips you have to offer would be great!