Four months old, all smiles, giggles, and a bit of chunk

Today was not only Sierra's 4 month birthday and her first snow, but her 4 month appointment at the doctor's office.  She weighed in at 13 lbs, 7 1/2 oz, nearly a pound less than her brother at that age.  Her growth curve makes more sense now with her smallish parents.  She's now 50th percentile across the board, weight/height/head circumference.  We decided to only give her one vaccine today because of her awful reaction at 2 months to having 3.  She vomited twice and hardly ate for days after.  So this time we decided to spread them out.  If she tolerates this one well, we'll go back in a couple of weeks for another, etc. etc.  So far so good, but she is fussy today, but was before her doctor's appointment.  I don't know what her deal is, the change in barometric pressure with the snow, a cold, or just not wanting to sleep, but I think she's cried more today than she has in weeks.  She's generally a very happy baby, very giggly and super smiley.  She still can't quite roll from her stomach to her back (but can easily roll from her back to her stomach and gets so mad when she can't get back) but I think it'll happen soon.  She now loves sitting in the Bumbo and is so much more interactive with the world.  She smiles at her brother every time she sees him and gets upset when left alone.  She's so close to sitting propped on her arms and now loves being in the Moby wrap facing out so she can see the world.  She's also finally playing with toys, especially soft ones she can gnaw and droll on.  Lovin' my baby girl more by the day.