S.Z.
Before you get nervous wait until she gives you the schedule. Then see how it works. also look at the state ratios for centers. I dont know what they are anymore she is probably giving your child the same kind of attention they would get in a center. Remember babies sleep alot and the older ones are more easily entertained than toddlers. He is probably not getting "one on one" attention but he wouldnt get that in a center either. I have worked in centers before and I prefer to send my children to in home care. Also if you really like her and are happy with her, and she doesnt charge an arm and a leg (like a center would) then talk to her about it. You have been with her for over a year, you should at least be able to talk to her. Ask to see her on a day when there arent any children there. Leave your son at home with Dad and talk, one on one.
If you think its not going to work with her, start looking for a cneter now. Pop in and see how the teachers interact with the group of children. They should let you tour, if not, dont send. That way you have pleanty of time to pick the right one.