Another babysitting question.

Probably in the wrong group but I'm just needing some advice here So I told everyone about the single mother who just started working. Asked me to watch her daughter and I of course said yes. 
She offered me 5$ an hour which is totally okay with me because I don't want to take money from her if she can't afford much. 
She's paying me for the first tome on Monday and her daughter will have been here 19 hours on Monday. 5 hours Monday, 3 Tuesday, and 6 today and I'm assuming 5 Monday. 
Which is 95$ 
Do you think I should get the 95$ I just feel bad. I just don't know how much she can afford. SHE told ME 5 an hour. 
Or should I just tell her after 4 days and it being 19 hours it's 95$ and then just tell her to pay what she can or how do I go about that?  Do you think 95 is a lot?