So I might finally get that sibling I always wanted

[Tilly1208]

...when I was growing up..and I’ll be 20 years older than them..
The mom to be is, I believe, 3 years older than I am, but I’m not sure because I didn’t even know that my father was going out with someone. I don’t know how to feel about this (apart from feeling slightly grossed out by my father despite knowing that he is of course free to live his life the way he wants to). I’m finding it hard to feign happiness but I don’t want to come across as bitter, but I am pissed.

It's not easy op but just embrace it, my friend is 32 years older than his brother!

Well, your dad will find it knackering having a baby and toddler again and will likely be assumed to be out with his daughter and granddaughter… Maybe this will help you!

Seriously though trying to find a silver lining, you may actually find it quite fun, hopefully you will get to do the nice bits of baby and then hand them back for the hard parts, like a fun auntie. (do not sign up for any sole care babysitting though!!) And it might give you insight on whether it’s something you want yourself in future. If you do have DC in future it will be like a cousin for them.

Totally appreciate it’s a shock though.

This may be outing but my 2 children are 20 years apart and they have the most amazing relationship. More like an auntie/niece relationship than sisters but they honestly adore each other. They have such a laugh together and youngest is so very proud of her big sister. When she goes to school things etc...... she tells everyone that her "big sister" is there.

Edited to add that eldest was also at the birth of youngest and it was an amazing moment for everyone. When the midwife came for home visit (it was a home birth) a couple of days later she said she had a little cry afterwards as it was so beautiful seeing big sister there at the birth and holding her baby sister so soon after birth. Big sister was also crying at the emotion of it all.

I know someone with a brother and a sister 20 years older. They’re good friends now at nearly 40 and 60ish. The aunt and uncle are like extra gps to her kids. Really friendly and supportive.

There's 23 years between my eldest and youngest (full siblings) they get on amazingly. Some of the ones with smaller age gaps, not so much 😂

This happened to a friend of mine. She was equally surprised (I think her Dad may have been too if truth had been told!).
15 yrs later, she and her half siblings (there was another 2 years later), her step-mum and her own DC all get on really well when they meet up and hire a villa together for a week each summer. She still says it's weird if she thinks about it so she doesn't and just enjoys their company. It took her a while to get to this position though!