Is it selfish or rude of me to not stay up late on the holidays?

Emma

My mom is hosting Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> dinner, which always includes games and some gift exchanges. Usually the celebration goes until around midnight or 1am because we start dinner around 7pm. This year is the first year there’s a baby involved (my 4 month old) and my sister is pregnant and due on January 3rd! So she will be extremely pregnant but she still plans to go to my parent’s house for this holiday.

I asked my mom if we could start dinner earlier, similar to how we have thanksgiving (we literally start appetizers at 1pm bc my sister leaves at 6pm to go to her in laws house). She said no, that Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> always goes very late. I asked her why, and she said that’s just the way we do it. So no real reason. I said okay, that’s fine, but I’m not going to keep my baby up past 8pm because he becomes hysterical when overtired. I let her know as politely as I could that they don’t need to plan around my schedule, but I will be leaving at 730pm to start getting ready for bed/putting my baby to bed. And I was going to stay overnight at my parents house but my baby can’t sleep in a super loud house so if my extended family is still over, we’d have to drive home (45 min drive) to sleep and won’t be there for Christmas morning.

I just don’t want to be a zombie on Christmas Day. I would like to at least have the opportunity to enjoy it. And there is truly no reason she wants to start dinner so late other than ‘it’s how it’s always been done’. My (very pregnant) sister also wants to start earlier so she can go to bed early. I told my mom that in the future when the babies are older we can stay up late with them. But my baby will not be fun if we keep him up past his usual bedtime.

Am I being unreasonable/rigid for not forcing myself or my baby to stay awake in order to celebrate the holiday with my mom/extended family? Should I just suck it up for the sake of tradition?