Everything I've heard about the "4th trimester" ends at 3 months. The doctor told us baby can't be spoiled before 6 months.

K is now 15 weeks and more-so recently, ALWAYS wants to be held or worn. I suspect it's more about being upright and seeing the world, but she is starting to be terrible in the car seat. She will start off making crying noises, but I feel like it's just the sound, and not real crying. But pretty quickly, it will escalate into full blown tears and sometimes spitting up, she gets so upset. But as soon as I'm about to take her out of the car seat, she often stops and smiles at me! Is she "testing" me already? Am I spoiling her by picking her up or taking her out when she cries now? This 3-6 month period seems so questionable - what is spoiling and what isn't? What do you think?