Child holiday-ing with grandparents

I love browsing this app but I’m not a poster! Hoping to get some advice if anyone has any to share, thank you 😊.... So my husband mentioned that my in-laws were going to “gift” our little girl a weeks holiday abroad when she’s around 5. I didn’t think much of it until they recently came to visit and mentioned it directly and in more detail. They want to take her on holiday abroad WITHOUT us. Due to a 100 mile distance, she has so far seen her grandparents only one weekend every 2 months since she was born (edit: no overnight stays I should add), so if it continues until she’s 5, they are somewhat familiar, but not enough for her to be comfortable going on holiday abroad with them (I wouldn’t think), especially without us and with no other children for company! I feel like she’s too young (won’t be able to communicate with me if she needed too), it’s also too far away (if anything was to happen), and far too long, I would worry myself sick. She is only 9 months, so still very young to be making decisions for when she’s 5 - should I put a stop to their planning now before they get ahead of themselves? Will I change my mind? Have you agreed to anything similar?

At the same time, Im not sure if I’m overreacting... we’re currently about to start the settling in sessions at nursery and I’m going back to work part time.... holidays, annual leave has never been so precious.