It is a risk what ever you do in life, I am fortunate in that when I went self employed I didnt have the commitments of children, a big house etc..
I also had a very nice nest egg saved from when I left the forces following a medical discharge.
It is not easy, as others have said, the admin can almost be a second job in its own right. A good accounting package is a must (quickbooks or others, get a good accountant too, I can recommend one if you are looking, she covers all the UK and works via email, video calls etc - shes affordable too)
You need a pot of money to get going and its surprising the overheads you have that you dont think of initially, In the early days, it seemed as soon as it came in the money went back out on equipment or tools etc.
Insurances. vehicle, Public Liability, Professional Indemnity, Sickness/Injury etc
Scheme memberships.
you need to put a bit away as a rainy day fund for van repairs etc.
Think of your advertising too, how will you bring work in?
In the early days; I questioned my decision, my physical health meant though I needed the flexibility of being my own boss and its now starting to pay off, I am seeing decent money come in with regular good jobs that fill the diary and am now booked up until late August.
Good luck.