I suggest you better invest now. There's no guarantee that the market will go even lower. It's been playing statically lately, and if you notice, it has gone low approximately 80% from its all-time high. Historically, whenever bitcoin hits a new high, it will seem to rest uncertainly, then will surprise us again by booming drastically. Given these facts, we can infer that anytime, bullrun can happen, and its current price is a good bet. If you are not convinced still and still lacks confidence in the recent movement of bitcoin, you can invest only half, then always be on the watch for unexpected turns.