Planning family to visit causing me stress.

Ladies I am so frustrated. I need advice. I am a army wife, my husband and I are in Tennessee but our family is in Maine. They have never visited but plan to around the holidays because we are due with our first child thanksgiving day. My mom wants to be here like as soon as I give birth but needs to get plane tickets soon before prices go up. I have a bicornuate uterus, my son is in just my right horn. We just had our 28 week growth scan and appointment. The doctor said that his percentile is 24 it was 40 at the 20 week. So it went down a bunch she said most likely because of my uterus. I got in for another growth right before my 32 week scan. Doctor said that if he is 10 or below I have to go back to the high risk doctor and have more tests done and possibly have him early for his own benefit. But I won't know all that for sure till mid October! What do I do?! How do I pick a time for her to come if I have no clue when he could possibly be here. Please someone give me advice!