I charge the same for a space too.

My thought process is that all ages of children have their own set of challenges whether they be physical, mental, or on the pocket book

I find infants to be more difficult on the body while toddlers / preschoolers become more emotionally challenging. As for the pocket book I think it depends on the child. I have one little one who eats me out of house and hold no matter what age she has been, I have some who are difficult on the budget because they love crafts which aren't cheap etc.

I think the only time I would give a reduction is for children in school full days, the reduction is in that I don't charge them for the full day, but hourly their rate is higher.