Careful scientists tend to say "this is the first time where we know what's happening before this we're unclear" And "this is where our model breaks down, may

Careful scientists tend to say "this is the first time where we know what's happening before this we're unclear" And "this is where our model breaks down, maybe {big bang singularity, big bounce, etc} happened before it" The big Bang (fast inflationary persiod in the early universe) is not one of those things? To my knowledge its well measured?