Everything in life is full of risk and nothing it ever guaranty so it is for bitcoin and that is why it is good to always invest what you can afford to lose and not investing your whole money, for sure bitcoin will go up and down, you could make profit, and you could make lost, it's left for you to take the best decision.
Yes, I agree with you, bitcoin is still the top coin up to now, but still its value goes up and down, of course this is followed by other coins, but I still believe bitcoin will continue to provide benefits for the future