Yes it is, get as many as you can while the price drop down again @3500 or you can wait till the price drop to 3000$ maybe that will be bottom of bitcoin and that will be the best opportunity to buy bitcoin.
That is why we don't have to buy 1 bitcoin directly because we need to have spare money to buy more bitcoin if the price suddenly down too deep. If we can save more money, we can decide how much bitcoin we need to buy now while we still have money to buy again later. You can buy bitcoin at any price you want but remember, you should have money in your balance just in case if the situations on the market changed in the next day.