The timeline for your case depends on a number of factors. The biggest factor is always how large of a settlement is at stake. If you are requesting compensation for significant losses after a devastating injury, the insurance company is more likely to delay your claim or fight it.
Other factors that can affect your case’s timeline include the availability of evidence, whether there was clear negligence or liability, whether the defendant thinks they can use the law to dismiss your case, how clearly your injuries are related to the accident, and so on.
Unfortunately, there is no way to predict how long it will take to get a settlement — or whether you need to pursue a jury trial in lieu of a settlement — until the last piece of paperwork is signed.