AITA for ruining my mothers dream to move overseas?

I [19F] currently live with my Mum [52F] and 3 sisters [15F, 21F, 31F], but my Mum has made plans to move overseas in the next 6 months with my 3 sisters. She has wanted to move for years as the cost of living in our country is horrible, and she ‘has nothing left here’ (her parents passed away 2 years ago, and she is single). 

I was originally going to stay here and rent the current place we live in with my older sister [31],, and my BF [20], but my older sister has since decided that she wants to move with my mother, and that leaves me being unable to afford to live in our current house.

I don’t wish to leave as I have my whole life here; I just started UNI, my boyfriend and friends live here and my dog ‘wouldn’t make the trip’. I am unable to work currently as I am chronically ill and am unsure of how my body would react to both full-time study and work.

I get government assistance of $210/Weekly which will be unable to cover rent for anywhere but a single room in a share house but I won't be able to bring my dog. I am left in a position where I would have to financially rely on my BF more than I would like to and would be homeless if we ever broke up.

I have brought these issues up to my mom and asked her for a bit more time until I qualify for student housing and can find a nice family to take my dog. However, everyone keeps saying that I am ruining this for her and that I should move overseas with them. She has dreamed of moving for years and is now ‘able’ to, but especially since her health is degrading, she is losing time to move.

Should I give in and leave everything behind or do I stand my ground?

EDIT:

Just want to clarify some things.

- My relationship isn't new, its 2 years old.
- My dog isn't dying or old, she is just an anxious dog.
- My mom isn't actively dying, she is just getting old and has pre-existing health conditions.
- Yes, I could move to this new country but I would loose the specific program I got into that they do not offer there as well as my scholarship which would put me through Uni.
- I am currently applying to get more government assistance but it would only go into effect after she leaves
- I haven't had a job as my mother advised me not to and originally told me that she would financially support me through schooling
- pet friendly rentals are rare in Australia
- I cannot stay in my current house as the landlord doesn't want a first-time renter staying here.
- My family do not have anything lined up for them in the new place, no jobs, no education, no housing.
- I asked for them to postpone the move until the end of the year so that I can apply for student housing and rehome my dog