You can buy bitcoin anytime as bitcoin is best and top most coin of this market. You can buy now if your view of holding is bigger as this market is volatile and it can also comes down but if you are a long term investors then you can buy any time as it has huge potential.
Actually you are right that bitcoin is still reamaining become the toppest crypto so always good to buy bitcoin anytime.
Dont always buy bitcoin in big money because its dangerous if you have no experience yet. So look for your experience and invest bigger after.