Help! How Hard & How Many Hours?

Hi.
I'm considering going to nursing school. I am scared to death after reading the posts about needing to forget that I have any sort of life outside of nursing school. I have two girls ages 9 and 12. I dont have custody of them but I am afraid that if i go into school that I wont have any time at all to spend with them after school or on weekends for 3 or so years ( going to CC for an ADN and getting prereq). Is this really the case? Realisticly, how much time should I count on banking for going to class and studying? In this senerio I wouldn't be working. My job would be school. I am an average student. Am I talking 60hrs a week or am I talking 80-90? I know that no one can give me an exact answer, but if it is 60 or less I would think I would still have time to see my kids and be a part of their lives. I want to better myself and be able to provide a better life for my family but I'm not sure i'm willing to go forward if it means that I will be forced to be completely absenst from my childrens lives. Is it realistic that I might be able to count on studing or going to class between the hours of say 8am-6/7pm m-f and have a good amount of time on weekends to see the girls? Any insight anyone could provide would be exteremly helpful. Thanks so much!!