AITA for not wanting my fiancés grandmother to move in with us?

Me (23F) and my fiancé of 6 years (26M) just started renting a place with no roomates. its a 2bed 2bath trailer. weve been trying to have a baby for a few years now but until then our extra bedroom is currently our gaming room. we also have 2 big dogs.we have 1 car as well. his grandmother (78F) does not own a car nor a home. she has been house hopping between her neice and her friend since me and my fiancé met. shes getting old and getting to where she cant drive. shes been wanting to move in with us because her neice is always at work untill 5pm, but i have my own life im busy with and my fiancé works 12-16 hours everyday. so my fiancé is thinking about moving her in. i have a few reasons why im against it; 1.) our trailer is completly furnished and we would have to get a storage unit to put our stuff in just to make room for her, but she has enough belongings to furnish 3 families im not kidding. she even asked my fiance where we would even fit her. 2.) my 2 female dogs dont like other dogs and she has 2 small female yorkies that she refuses to get rid of. 3.) i am the woman of my home and take care of it, my fiance and his grandmother are very close and she favorites him over anyone. she has 6 kids and hasnt talked to any of them since before i met my fiance because she claims she "doesnt like her kids". i dont want this mother figure living with us telling me this is how she does it so i should do it like that. not to mention i know that will cause me to resent her and cause problems in our relationship. 4.) if she moves in she will live with us permanently considering she doesnt really have anyone. all of the caretaker needs will be pushed on me slowly over time and im too young for that. were not even married yet. we will loose 100% of our privacy and our freedom will be effected more and more over time. i have bad driving anxiety so my fiance would have to take off of work everytime she has a doctors appointment. we havnt even told her she can move in and shes already talking abt if she did then she can put her money with my fiances and we can all 3 go buy a house. i DO NOT WANT TO BUY A HOUSE WITH HIS GRANDMOTHER. 5.) i have pcos and if any of you ladies know what that is, you know i struggle with infertility and stress is a major factor in that role. if im always stressed out about his grandmother while hes working all the time it will effect my body, mentallity, health, and fertility. and when i do get pregnant i need privacy becoming a new mom and not to mention we will need toom for a baby. are my points vaild or am i being selfish?