It took less than 3 months in 2017 i to reach 20K starting below 4K. And then everyone knew CME and CBOE won't buy actual bitcoins. Now it is different. It is hard to predict what will happen in the next few months. It depends how quickly the main ETF buyers will adapt to the new opportunity to buy bitcoin ETF's. May be there will be a rush, may be not. And may be  some will be dissapointed by the slow start and dump their coins. But in the long run the supply shock will make the difference of course.