Short answer is: no one knows. It depends on how much trust people will continue to place in the currency, as well as governments or other institutions trying to regulate the currency.
Bitcoin will keep growing untill there is time when everyone will know it from all part of the world and it will be the highest, it also depends on capacity of people they can afford to buy Bitcoin. 2017 was a blooming year for btc and with the growing popularity of btc the value is expected to grow over 10,000$. I don't know exactly how far it can go but we are far away from it's highest price.