To add to Jonathan's answer: "make/made it in" implies that it was really difficult to achieve. In your example, there was not much time. Another example "despite the snowstorm, the flight made it in" Another example is being in a really long queue for a nightclub. Finally you get in, and you might say "Great! We made it in!" I think the grammar is fine, it's just a bit informal.

Thanks, Jonathan. very helpful.

It means the same thing. For example; if your brother has been out of the Country and he has arrived. You can say; “My brother has made it in”, it’s not great grammar but is often said in American English.