One of the scariest things/concepts, I have been introduced too is the formula for Big O notation.

What is this thing? Is this english?
Well, good news, it’s 2021 and there are so, many resources on the internet.
One resource that made the muddy water more clear for me is the REDUCIBLE channel on YouTube.
Check this link out and maybe you will be a little more confident when discussing Big O Notation with others.
https://www.youtube.com/channel/UCK8XIGR5kRidIw2fWqwyHRA/videos
Hope this helps!
Good Luck, with your Coding Journey Friends!