It's better to invest in bitcoin than never, not just bitcoin but also other cryptocurrencies. Imagine if we invest way back 2013 with prices spiking as high as $1,242 in November of that year before retreating, REGRESSION 
. Hurry up and invest.
The example you used is true but not only 2013 did this thing happened, the price of bitcoin will increase, it will later retrace but not retracing back to the initial price but will be at a higher price, increase back again and reach highest price again. The best time to invest in Bitcoin is when the market is red, when inexperienced people will be afraid to buy but experienced people do buy at that time which will make its price to increase. I do not see anything worng there to invest in Bitcoin and never afraid of what will be the outcome because the person will later gain after a long period of time.. Hurry up and invest.