The knowledge you need to have in Bitcoin before you can start is the basic knowledge, yes you don't need all the knowledge before you can start, all you need to know at first is what Bitcoin is all about, how to create your own wallet, and how to buy Bitcoin and hold, this three things are the most important thing you need to know after knowing them you can start your accumulation journey, now when you must have started it is also important that you try in knowing other things in Bitcoin like finding out other accumulation strategy and knowing the history of Bitcoin growth and how is going.
Knowing other strategy is very important because you may discover a more better strategy that will make you feel more comfortable like me when I started Bitcoin investment I didn't start with DCA strategy it was when I came into this forum that I discovered other strategy and I decided to go with DCA strategy because I loved it, and knowing the history of Bitcoin growth will help you will help you feel comfortable and remove fear from your eyes.

You don't have to wait for a dip to happen before you start accumulating, what if dip don't happen, waiting for a dip is a waste of time, why not use the DCA strategy and then start accumulating, this strategy will help you even buy during the dip.
You are not late you can still start your accumulation journey and succeed Bitcoin still has a long way to go, it is still growing.