I've been in bitcoin for a long time and I've only ever bought more. I am not at all against you buying bitcoin, I am still a buyer at the current prices, in fact I just bought more to celebrate the ATH.
BUT.
We're at least at the start of a new bubble. The bubbles always work in the same way every four years: price goes up, media attention goes up (this is only just beginning now), the price pumps to never before seen highs, speculators and gambling addicts throw in all their money, and then the price crashes and the speculators and gamblers sell out of fear.
If you want to buy bitcoin, good for you, but I don't think now is the best time to start unless you can stomach one, two, three years of losses. If you want to get into bitcoin it may be better to wait for the next crash, and I mean like 60%-80% down from the new ATH.
Also, not your keys not your coin: If you want to buy bitcoin please learn how to self custody.