I have to chime in here too. You have probably heard too many of our NAWTEEDAWG stories and want to get a head start on Keegan, but I wouldn't worry about a submissive roll unless you have the ALPHA QUEEN of a puppy, and you don't, because I had her. I used the the submissive roll but really didn't find that it made that much of a difference anyway. Karen is right, consistency of expectations is the best thing you can do for your little girl.
Walking through the door first is a good practice. One thing that a dog trainer taught me (which I wish I would have know sooner) was when you teach a command, such as "sit", you should use it with a release command. You say...Keegan, sit. (Only say the command once) When the dog sits or you help it into the sit position, praise her with enthusiasm. What you want the puppy to do then is to stay sitting until you say "okay", or some other word that denotes the puppy doesn't have to sit anymore. If the puppy gets up after sitting, you say, "No, sit". and put her back in the sitting position. Then "okay" and happy, happy, what a good dog and she can get up. You would want to start out with making her stay in the sit position only seconds, and gradully increase it to a little longer(10 - 15 seconds). You have to gear this to the puppy's ability to grasp at this very young age and like others said, remember she is just a baby. You are not into training sessions, just a little here and a little there interspersed throughout her day. We are not talking about a sit-stay here for any length of time, just getting the puppy used to understanding that "sit" doesn't mean sit down and then pop back up right away, it means sit until I am told I am told "okay". Such as exercise is also establishing you as the gentle leader of this pack.