I have a good relationship with my mum and she helps us with childcare, which I'm really grateful for. My three children love her and she's always been there for all of their birthdays. She told me yesterday that she's booked to go on a 10 day holiday with my sister and her husband next year... two of my children's birthdays are 9 days apart, and this holiday covers both of their birthdays. It's the only holiday she's got booked for next year so far. Apparently they "couldn't fit it in at any other time"...though the whole year is available as far as I know as she's retired, and my sister and husband don't have the kind of jobs where annual leave is restricted to certain times. I can't help but feel a bit upset that being at their birthdays isn't important to her and that she'd rather be on holiday with my sister instead, but am I being unreasonable? I haven't said anything to her, but wanted to gauge opinions on whether I'm being ridiculous to feel this way as I'm genuinely unsure