Travelling with baby 3 weeks

So we've been trying for soooo long, and we've finally conceived 🥰🥰

We have a holiday booked for 4 weeks after the due date and we can't get a refund on any of it.

Has anybody flown with a baby at 3-4 weeks? I know of I'm late it could be just 2 weeks.

My airline says it's fine, midwife says it's ok. But Ive read some negative comments about flying with such a young baby.

The flight is only 3 hours

Has anybody else done it????????????