felt guilty

i think it's not a big deal or what but i sound demanding to my mom when she asked me if is it required really to buy scientific calcu and i said 'yes it is' like i'm trying to convince her that it's important as a incoming stem student then after that i feel guilty sounding demanding even tho i'm just trying to convince her T^T i just feel guilty because she's the bread winner in our family and she's paying our expenses. i feel like i'm gonna cry whenever i relate to her problem :<