Career change at 40.

I am 40 and have never really had an amazing career that's gone anywhere. Has anyone managed to successfully change careers at 40 after not really having much work experience in that area? I want to get involved in business admin after working in childcare. I haven't got a huge amount of work experience in any area but have a lot of life experience (single mum having survived domestic violence which has left me with huge anxiety issues and low self-esteem - yes I see a psychologist for these issues). I am completing a certificate 4 in business admin. Can anyone please suggest ways I can change my career? I was also thinking maybe I could try and get some volunteer work.