Introduction and what do you think about this?

Hello, I live in TN and my husband and I are in the process of being approved as foster parents. We were told during orientation that we would get a call by our third class from our home study writer to set up our home study. However, we finished all seven classes without hearing a peep. One week after finishing, we got a call from our case worker directly (we had been given his name by our class instructor) and he said he was going to do the home study himself. He scheduled all four visits within the next two weeks of each other. He was very interested that we were willing to take sibling groups (even though many have said first time foster parents only get one child, he wanted to know if we had room for 2-3). While I was on the phone with him I asked how long it would take after his visits to get officially approved and he said "well... we have 120 days" and left it at that. Do you think if he's rushing to get all four visits in, and saying he's interested in approving us fast (so fast he's doing it himself instead of waiting for the home study writer) he will really wait the 120 days? How fast CAN it go? We were supposed to have a meeting with DCS before our classes were over but that got cancelled so we weren't really ever taught about the process of how being approved or getting a placement works. What should we expect? Our Timeline: Orientation: 9/2013 Fingerprints: 9/2013 Finished Classes: 10/2013 Call from Caseworker: 11/4/2013 First and Second Homestudy: Scheduled for Week of 11/11 Third and Fourth Homestudy: Scheduled for Week of 11/18