If you're planning on holding the coins long term, then get them now; difficulty is increasing and supply is increasing. When talking about short term though, maybe wait for more price dips before purchasing.
Actually, buying bitcoin is a good idea and prefer to hold it for a long term is a better idea where you can assure that you could earn much profit and money. In addition to that, you should buy now because as of now the price of bitcoin is not yet high and its a chance to buy a bunch amount of bitcoin.