can't,don't want and want

what the difference between this 3 words?
can't,don't want,want....
i hope i can be stewardess but i cant do it rite now....
cause i still studying,and my height doesn't reach that condition...
this is what i want...
everyday study is not the things i want....
that is the things that i don't want....
but i cant stop....
this is because my mother hope in this family got someone that can realize her dream...
she want to saw her daughters or son to get a high education eg:degree post(minimum)...
i cant obey her....
she put a lot of hope on me...
so what i can do?
what i can do now is do somethings that i don't want to do and keep my dream in my heart and mind...
not because i don't want to put effort on my dream...
is because i have the responsibilities to realize my mother dream...
not because i just know how to dream,is i just can dream for it....
that is the only things i can do....