I don't think we can see bitcoin back to 20K this year, the recent market has been falling sharply, and this year it is likely to be a revised year, just as it did in 2014.
Maybe this will be a revised year, maybe this will be a boom year. The crypto world is very volatile it needs some form of stability.
No one can answer this question if when will bitcoin will reach that value again. We people, are just all hoping that as soon as possible it will pump again. If there are more investors that come and support bitcoin truthfully then surely it will make 20000$ value happen again, or maybe more than that. As of now, we only need to wait for it.