Is the Glucose test really necessary?

I wasn’t able to do it on the day of my appointment when I was around 24 weeks because of insurance issues and my doctor says that there’s a time gap to take it, I’m 29 weeks and 2 days and I’ve called my insurance several times before and they say it’s going to take a long time to get everything sorted so I feel like I’ve missed my chance. And I cant hurry that process more than I’ve tried, and my doctor just tells me to get it done. Like I seriously can’t do anything else than what I’ve done. So I’m worried.