DD1 was 12 months and 5 days the first night she was left to wake up with someone else. I went into labour with DD2 at 2am and my parents came over to look after her. She woke up with my parents, and then my husband was home with her by about 10.30 am. I was home with them all that night. The next time would have been when DD1 was 3 or so and DD2 2 or so. They have only ever stayed with my parents, who they see multiple times per week.

I think they're being very unreasonable to put any level of pressure on you whatsoever at this point. Babies aren't toys to be handed around on a whim.