No colostrum? 37 weeks

Wondering if I'm alone in this. I'm currently 37 weeks pregnant and thought I should start trying to harvest some colostrum. I've followed the advice I can find online, videos etc, but I can't seem to get anything at all out of either side. Slightly concerned this may be a bad sign for my ability to breastfeed. Has anyone had a similar experience, please? Maybe I'm just trying too soon and my colostrum will come in a bit later? TIA x