there probably is another way, but probably not pratical, but you never know, it might be possible

when your a british citizen, go back and live with your mom for a year, then go and live and work in southern ireland or any other Non British EU country, , after a few months apply for a family permit for your mom, it could be really difficult for them to refuse, then stay there for a few months, then head back north and apply for a family permit for your mom to join you..