How long to colonize from liquid culture syringe? [Medicinal]

First time grower, long time enjoyer - I did look first for the answer to my question here but couldn't find it.

I injected a grow bag with a liquid culture syringe 12 days ago and don't see anything yet.

I know it can take weeks when growing from spores, but I sincerely thought culture was supposed to colonize in a fraction of the time. When do you start to worry?