Go for it! They want to share this with you, I say fabulous.
Honestly some folk on here are so negative!
DD's first flight was London to Tokyo when she was 18 months. Yes it was long, yes we thought it all through, planned, prepared as much as poss etc.Hardest thing was the jet lag tbh once there.
If you can choose day time flights, all round easier.
She will have her own seat and it will be fiiiiine. Make sure you book her in for a child's meal if they have them on this route, it's so short, and if you are still feeding her at that point thats a bonus on the settling, comfort, ear popping thing.
Ive been on flights where adults have vommed through turbulence, poss booze, It's not just a child thing is it?!