How do I make this stop??

For comparison:

About a week old here having her first bath

Almost 4 months old in the same bath seat!

Where did that time go?? I thought I was going to be pregnant forever and now my baby is almost 4 months old!! How did that happen?!

Things Maddy has been doing lately: She has really learned to grab an object when you hold it in front of her. Everything goes in her mouth and when she is not holding something, her hands are in there. I think she has discovered she can make noise also because she "talks" all the time now! She also can sleep in her crib but because the outlets in her room don't work, I have to keep replacing the batteries in her monitor and I can't do that everyday. So she's been sleeping in her bassinet so I can hear her when she wakes up. We are getting that fixed soon though hopefully and she will be sleeping in her crib for good!! Also, she's got great hand eye coordination for a 3 month old, I think. And she has more of an attention span for books now. I try to read one to her every night before I put her to bed.

Things I am getting a little concerned about: My bible (What to Expect the First Year) says that babies should be laughing out loud by 4 months. She has laughed a few times but it doesn't happen often. I can tell when she is happy or excited because she kicks her feet and flails her arms but she doesn't laugh. Also, she will NOT turn over! She did it a few times a couple weeks ago and now she just won't do it! She spends plenty time on her back and on her tummy, I try to convince her to do it but she just won't. I know all babies develop at their own pace so I will give her a few more weeks. I guess that's pretty much all I can do, right?