This period do not encourage trading or investment but at the same time when price is down is good opportunity to buy cheap and when its explode you will gain it. Nothing is lost in bitcoin, those holding for long now are the great benefactors but if you buy this period is more safer.
If I have money now, I would buy half of bitcoin because in next three months it will double the current price. This is real because it always occur this way after 5 years remember in 2011 and 2017 from the market charts and caps. And this year will break more even.
Obviously buying cheap is the way to go with any investment but I think that you do not really capture the essence of the problem here. What is cheap? Without knowing future prices, we have absolutely no frame of reference for "cheap". So we buy at we think or hope to be cheap.
Furthermore you should be careful about things like "in next three months it will double the current price". You have no possible way of knowing that. It could double or triple in the next week. And you would never be able to predict it.
It might also takes half a year or a year for it to double. Maybe longer.
Giving such predictions is setting up yourself and others for failure and emotional selling because you are sowing a seed of impossible hope in your/someone else's mind with such detailed predictions.