That's a question that really you can only answer yourself as only you know what risk tolerance you have. Understand that investing in Bitcoin can give excellent rewards but as with all investments the level of reward is proportional to the level of risk.
If you decide that you do want to invest then buying a dip like this is a good place to start. My advice would be not to go all in but just buy with a small part of your investment capital now. That way if the price falls further then you can keep making small purchases all the way down and get a good average entry price. If on the other hand the price resumes going up from here then you will not have missed out entirely and can still wait for the next dip.