It will be very difficult to dump the market further(it is possible, but it will be very difficult and dangerous), because the miners are already working at a loss on some coins, like ethereum. Bitcoin almost fell to mining cost price, so, i think, it worth to start to buy now.
No, Still if we are going to choose and decide, now is not always the best time, there is always a time that is exact and proximate in order to make decision, because at the end, if we just decide and decide, we can be regretful for the outcome. What we need to do is to be sure to our choices.