It is never too early to apply for social security disability benefits.
The law says that you have to be out of work (or be expected to be out of work) for one full year to be eligible for social security disability benefits. There is no disability benefit for someone who has been out of work for less than one full year. If according to your doctors, it looks certain that you won’t ever be able to work again due to the injury you suffered, it probably is not too early to apply for social security disability benefits.