Why is my mum so OBSSESED with cleaning?!?

i'm 18 and ever since i can remember, my house has been SPOTLESS and my mother was always cleaning, like ALWAYS. there are never dishes in the sink, or out of the sink, straight after dinner we have to wash them and put them away or she gets angry, she vacs our floorboards every morning, even though they literally are very clean from the last vaccuum, if anything is out ofplace is drives her crazy, our rooms have to be extremly tidy etc and i would be fine with this, its just that she makes me feel so guilty if i don't help her and clean as much as her, and she gets so pissed off just because we don't have the same crazy standards as her, its like she makes me feel like im a dirty unclean person if i am not the way she is, and i am really quite tidy. I go to my friends houses and even though i know theyre normal, to me they seem extremly unclean and filthy because of what i am used too. I know her mother is like this but worse, and it all started from when they moved here from Yugoslavia, where they lived in poverty, and my grandmother was obsessed with keeping her beautiful new house tidy with all these cleaning products suddenly available to her, and i guess the shock of not being dirt poor anymore would of contributed, do you think this is psychological issue my mother has due to her childhood or is she just reall really clean?