It is possible that Bitcoin price reach $250k, but it will soon after that drop under $100k. Also I would speculate that more possible time frame is 24 months and not 12-18.
The same pattern as it did with its past all time highs. $250k is such a huge amount to think of and IIRC, there's one famous crypto guy that has predicted this, Tim Draper.
(
https://cointelegraph.com/news/tim-draper-doubles-down-on-his-250k-btc-prediction)
2017 Bullrun had made this person become famous as he perfectly projected it but I don't think he gonna be right again this time. $250k is really high and never in mind to think we can reach it, maybe $50k is close to reality than this. However, it was him to project and give his optimistic speculation (and I believe we all that the same) and it's up to us to draw any conclusions as anyone can make their opinion as well. But just to say that it looks impossible and never have to expect for it.
Let's give him the credits if he actually made it last time but this time, a lot of doubts and they are not pushing us to believe them that the price will go exactly as $250k. I'm part of those people that are waiting for the all time high and if it suddenly appears, I'm glad to see that but if it didn't, that's what I'm expecting. But the given timeframe of Tim is longer than what @OP is predicting, it's earlier. This is a waiting game.