Exactly. New cases have no carbon fouling inside, which actually acts like a lubricant when resizing. That's why wet tumbling, which can strip out the carbon fouling inside the case, soetimes makes for harder resizing and reloading.
You can also try tumbling new brass in some old, dirty tumbling media. It will leave a slight dusting within the case, which will make for easier resizing and reloading. That's what I've always done with brand new brass.
Also, take out the powder nipple, and polish it with a dremel polishing wheel. That will also help the brass from sticking to it.