In Home Daycare

I currently babysit for a family in their home for their 2 children - 4 and 2 years old and their mom is currently pregnant with their 3rd - daily 7am to 4pm . I've been thinking that I would like to start doing this in my home but I'm not sure what to charge for this (I get $100.00 a day for babysitting now) . I'm the mother of 3 preteen/teenage children with at least 20 years experience. I know a teenage girl in my neighborhood charges $10.00 an hour when she babysits. I'd be interested in what anybody thinks would be an appropriate amount to charge. I live in South Huntington, New York (Long Island)