This is Mackenzie at 7 months. I believe she is going to be bigger than her big brother. She started sitting up at 6 months and Ethan didn't really start sitting up until about 8 months. Although Ethan did start sleeping through the night way before Mackenzie did. I just think Mackenzie knows that at night is the only time she gets with her mommy with out her brother. I love snuggling with her.