Your mom is SO right. Moms are always right.
Before drawing, go through "tutorials" sticky (in Critics Lounge main page) and learn what "vanishing point system" stands for. And how to use this.
Basically, your room has NO perspective. I drew a quick and dirty pic to show how you should have started, before texturing and coloring > notice how all lines vanish into one point:

Before drawing, go through "tutorials" sticky (in Critics Lounge main page) and learn what "vanishing point system" stands for. And how to use this.
Basically, your room has NO perspective. I drew a quick and dirty pic to show how you should have started, before texturing and coloring > notice how all lines vanish into one point:
