New moms

Ok so I'm 5 weeks postpartum with my second. Everyone in my town is prego, which is awesome, but what's really starting to get me is the ones who just have their baby, and they know EVRRYTHING! Literally they think they know everything. This is my second and I'm sure as hell no expert! I just find it incredibly irritating m, a couple have even been arguing with me about things, the one I'm particular has a 4 month old. Granted like I said before I'm no expert, but I have a 6 yr old who is healthy, smart, beautiful, and everything else u cld imagine, my 5 week old is right on track too.. am I just being over the top with this? Anyone else experience anything similar??