Abby is now sitting up... and she isn't even 5 months old yet!
I was about to take some pictures of her tripoding ( sitting forward propping herself up with her arms ), but to our amazement she started sitting upright by herself for about 2 minutes!
I captured the moment on my video camera as well ( check back here for the video in the near future ).
Since this initial moment she has been regularly sitting up. I guess she is raring to reach the next developmental marker.
She is growing up so fast. Before you know it she will be crawling and walking all over the apartment! We have some baby proofing to do before that happens :)