This could both be the same problem, my RSS is displaying the first item as the latest. If my RSS is only displaying 3 at a time then obviously you don't get to see the latest stuff, just the first three entries.
Anybody else had this issue? I'm using silverstripe 2.4.5 with the latest blog module and igoogle agregator.
I just came across this post looking for something else, I had completey forgot!
So I now know this answer and thought that I would share. Basically the reason for the RSS picking up the first three posts is because you have to re-order your blog entries using "drag and drop" to put the most recent entires and the top of the site tree.
Now I just need to figure out how to make this automated each time you create a new blog entry page!