any time is the right time to buy bitcoin if you see from the historical chart that BTC always sets a new record of ATH every bullish cycle, you can be buying at the top and you'd still profit if you're patience enough but as mentioned by other people, just do DCA if you're confused. even buying above $100k is fine if you just keep DCA-ing until price increase exponentially from your cost average and you can already realize your profit.

or if you're really care about risk/reward ratio, then just wait until bearish cycle comes in. it's as easy as that.