Doubts and fears are very natural, and it is the nature of every human being. It is not a problem as long as we do not fall into that fear or doubt and make us never move to start collecting bitcoins in our portfolio.
It is interesting to read your words regarding "I believe that no time is wrong for an entry point to accumulation some Bitcoin" because even if that is true then an investor who buys bitcoin must hold it longer, unlike when they buy during a price decline. For example someone who buys when bitcoin hits the last ATH, then how long does it take them to be able to turn their portfolio into a profit? here requires a very strong mentality to be patient to hold it, because if not then they will be frustrated and sell it at a much cheaper price.
Not everyone can do that, especially if they're someone who doesn't have a lot of patience.
All trader ever in position doubt and fear when investing their money in bitcoin or altcoin exactly facing moment with price dropped drastically, its nature of human being how to face with their investment happening later drop or not. But don't give up for accumulating and buying bitcoin how many possibility based on our financial having. Bitcoin and altcoin trader have strong mentality and more patience facing bad moment when bitcoin drop and keep continues reinvesting if their target with long term investment. Don't give up when looking current Bitcoin or altcoin have lower price but take it as very good opportunity by accumulating as much possible not only with bitcoin but also some potential altcoin worth for long term holding.