I know her as Megan from the Progressive TV ad or the gal from the latest Milo's Dog Treats TV ad. Melamie is very recognized and memorable by her voice, however she was on Notes from the underbelly and I don't remember her from that! Also found that Melanie has worked with Yoplait and 1-800 Dentist.
So I would say between 8 and 13- depending on the maturity level of your child. In texas there is no law that stipulates when a child is old enough to stay home alone. In fact there was a news story on this just this month (I'm pasting the details for you below.). Good luck!
Under the Texas babysitting laws, there is no minimum age to start babysitting. In many areas, teens as young as 11 baby sit. In general, younger teens should start by caring for siblings, or for one child who is between the ages of 4 and 8 years old. Gradually, increase the number of children and expand the ages cared for.