Glucose tolerance test

Right...I'm in uk and I'm 27 weeks and 5 days. I've had to book this test but I've read you have it from 24-28 weeks..I've only just been told and the earliest I can get it done is the 22nd May, by then I'll be 29 weeks. Can you still get it done then or will that miss the window? I'm getting blood taken and drink the drink then rest for 2 hours and go back to get my bloods taken again if that matters. Thanks in advance, I'm not even a stressy person but this is stressing me out 😩🥴