DH and I went on a belated honeymoon recently (we waited until we felt comfortable leaving the boys) it was for 8 days and although we enjoyed ourselves it was hell! I missed them so much and I skyped them every day and thought of them every second! I don't plan on leaving them again anytime soon! The only reason I went was because my mum offered to fly over from WA to NSW to have them, she is the only person I'd trust with them for that long, I felt more comfortable because it was my mum, whereas I wouldn't have felt ok with it if it was the ILs despite how much I love them! They also say things along the lines of sending the kids over for a holiday, but the kids are 3 & 2 and ILs know we wouldn't even consider it for several years

Anyway long story short! She is your DD and it's up to you when you feel comfortable leaving her! You can only be honest with them! Eventually they'll get the picture and stop asking and wait for you both to be ready.