At what age did your twins have their first international vacation?

Our 16-month-old twins are our first children, and we’ve had a full-time house help since their birth. We’ve become so dependent on her that it’s hard to imagine managing the kids on our own. Since they were born, we haven’t had a proper vacation. I’d love to take an international trip as a family of four, but I’m unsure if we can handle everything without help. Any suggestions or experiences to share?