"Can I move out at 15 if I'm unhappy ?"?

I am 15 and am goin to turn 16 in March i live with my sister her bf n their baby. Ive stayed with them for about 3 years now and i am unhappy, i have the option of going home to live with my mom again but if i go bac thier i know that ill be even mor unhappy than i am here in arizona. im bout to get a job and im doin fairly well in school with As and Bs so if i were to hold off til i turn 16 and save the money that i earn and still do good in school do you think i could move out on my own if i could afford it if i could be happy cause thats the main reason i wanna move out is to be happy. if i could take care of myself n have my responsibilties and took care of them. If i plan it out and hav a plan as to how im goin to do it and fallow that plan if it works. cause if not i can jus save the money i make workin and run away cause that was my 1st plan but i was thinkin that this is a better and smater idea. What do you think