Hi there!
I am also a mum of 2 boys they are 1 and 3, I started my nursing degree last September and I know exactly how you feel however I am sure that the family as a whole will benefit from a mummy who is happy and fulfilled, we all have to work these days to afford things and when you qualify the shift working will benefit the whole family, so dont feel too guilty now, when you tell the kids when they are older i am sure they will be very proud of a mum who has a profession! x