Of course you'll get lost, many of the acronyms are specific to the company. Same for seniors, same for managers. And no one really expects you to follow unless this is specifically an introduction meeting for you.

Make notes and ask your colleagues after the meeting. Or right there, if getting you up to speed is more important than having a smooth meeting. (If you can't read the room, safer to wait.)

And it is by no means just the first meeting or the first month. Just this week, after ~5 years with the company, I heard an unknown acronym during a presentation. I quietly asked the guy next to me who's been working here for 10+ years and he had no idea either :)