Follow your heart and do whatever you think will benefit you and your mum.
Do you think by lending that sum of money from your mum, your mum will suffer?
If the answer is no, then borrow the money and set a small sum everymonth to pay her back.
Also think carefully if this is a course you really wanna go for and would help you in future.If it is,no point missing this opportunity as once you have finish the course, you would be able to get a job and not only will you be able to pay your mum the amount back, you may even provide her a better life in time to come.
Also do consider who will look after baby in the evenings while you are at the class. If mum is willing to help you then you can go for your course with a peace of mind.
But if all is too tiring/troublesome, mayb you should settly for your current job and appreaciate what you have now.
Of cos, there is no harm in upgrading yourself.
Hope you will consider the choices you have carefully and see which will benefit your baby mum and you the most