In purchasing Bitcoin, it will really depend on ourselves and don't let other people influence us and buy it without knowing well about Bitcoin. Of course we have to do our own research on the right time to buy it and it would be better for us to have a good plan before buying it and can survive for a long period of time, you are right that no one can correctly predict the price of Bitcoin and it would be better for us to really understand it ourselves when buying it and not have to be influenced by other people.
We have to make a decision with the help of our own knowledge because we cannot follow the suggestion of others as we don't know what is going on in their mind. People always ask about their investment plans from others but I think if you are using your own money so use your own mind to overcome the risk.
If we get enough knowledge about Bitcoin and the crypto market then we will be able to make predictions as others can because no one has confirmed information but everyone is reading the market chart and learning about the past so they assume about the price in future.
Investment decisions must be made based on your own available knowledge of the BTC market as there are many investors close to you who may not give you positive advice most of the time. I am a victim of this myself and I myself take very careful investment decisions.
Instead of relying on past price charts, you can research daily price charts and buy and sell statistics to make some predictions about the market.