we shall assume the price the BTC will have in May will be the maximum for this cycle?
Should we sell in May?
Trading purely based on your assumption will definitely lead to big disasters. You cannot predict the timing of cycle of price fluctuations just from past history. If you have any technical analysis to find out where market will turn up then you may proceed. Moreover all technical analysis are providing only the price ranges not the timelines. I mean you cannot make your trading on timing based but only on price ranges because technical analysis provide only signals on price levels.
As per usual, in the end, where the markets will go will all end up going to depend on supply and demand, not with dates and time spans.
I guess this is thing where most traders are slipping down and makes mistakes. They believe into their own assumptions and based on their emotions they do trade and not as per technical.