Advice !!! Picking Mum or Dad Over Christmas

I need advice !!

Okay so a little backstory.

My parents split when I was around seven. I would spend every single Christmas Day with my Mum apart from one year I spent with my Dad and my Step-Mum.

Over the years, me and my Dad had awful problems and would spend long periods of time out of contact. It is only in the past two-three years that we have found ourselves on good terms again and have actually become close.

Last Christmas, my Dad and Step-Mum went to my Step-Brother's for Christmas which meant that me and my sister could go and see him for an hour or so; this was the first time I'd seen him on Christmas Day in around 8-9 years.

Overall, I'd estimate that my Dad has missed around 10-11 years worth of Christmas with me and my sister; his only children.

This year I live with my boyfriend but will be going to my Mum on the 23rd to spend the Christmas period with her; however, my Step-Mum asked if I would like to spend Christmas night at their place as it would mean the world to my Dad. I said yes and that I could come over after dinner maybe like 7-8pm.

So my Mum is devestated and thinks I' angry woth her and I love my Dad more or something.

She's making me feel SO guilty. How do I choose between them. I feel she's being a little manipulative and unfair. My Dad never see's me at Christmas and I'm his child too, not just hers.

Do I go to my Dad's Christmas night or spend all day with my Mum so I don't hurt her feelings?