Do not go with someone's prediction and invest believing their prediction. Anything can cause crypto value fluctuate. 2018 has been an year for buying coins with cheap rates and you are aware of this. Trust in bitcoin and crypto coins. Have a complete study, pick the coins you find potential and invest. Just make sure, crypto value fluctuates and none knows when values would spike up or fall back. Prepare and train yourself to be familiar with crypto currencies movement. We have short and long term profitable coins. Choose and abide to the timings accordingly.
In fact, making investment decisions based on someone's prediction is something that is not right. You should always find what makes you want to invest in a market and not just because you want to make money in the long run, but for the fact that you believe in its future and you are ready to take that risk knowing that it is going to be worth it in the long run, if all things end up working good to your favor.
Buying bitcoin now is a good chance that a lot of people may regret missing in the long run, but I guess it is something that is normal; as some as smart, some will not be smart.