Career change - Becoming a Maternity Nurse

I have been an English teacher for 13 years and have a family. I am now looking into changing careers and would like to become a nurse in the next 5-10 years (trying to be realistic with little ones and all). I would have to take a bunch of prerequisites and it would be a long road, but well worth it to me. I would definitely want to be a maternity nurse, and I am wondering whether it would matter if I had an ASN or a BSN for this particular nursing job. Also, how long would it take to get into maternity after passing the test and becoming an RN?

Thanks!