My trading journey is spanning to almost 2 decades now, and if I remember clearly, it was between 2004 and 2005 that I started trading. I can't confidently call the exact year for the fact that I first started gathering trading materials without acting on them before I later started reading and training on what I read.
As you can see, this was years before Bitcoin was even born and I can confidently say that the price of Bitcoin was still Zero ($0) when I started trading. But it took me years after Bitcoin was born to actually open my first trade on it and the reason is because I am already trading other aspects of the financial market.
I would guess that what they were trying to say was "what was the price of bitcoin when you first started to trade bitcoin", not when you started to trade in general, yes the wording was a bit wrong because it looks like there is a loophole and your answer would be a correct one considering how it was worded, but the mindset must be learning about the price of bitcoin when you first started trading bitcoin itself.
For me personally I always say that it was under 200 dollars for example, I can't possibly remember what the exact price was, but it was about under 200 dollars and I started to invest, not really trade because at the time it wasn't really trading worthy to me, it was mainly investment and I bought and hold and when it went up a bit I sold and bought something, I kept doing that up until it was already around 20k+ and then I started to trade, been doing that ever since and it's quite fun.