how to explain to 2.7yo that her soon-to-be-born brother will be sleeping in our room?

[redundant]

hello, as above really. Have been trying our best to prepare DD for her sibling arriving next month - not really sure she gets it but we'll see. We have moved her out of her room (as baby needs to have the room next to us) which went well - she loves her new room.
But for the first - well at least 3-4mths (not sure I'll be able to stick it for 6 mths but we'll try) new baby will have cot set up in our room and will be sleeping in there.
Sleeping in our room is likely to be seen as the holy grail in our daughter's eyes. Any tips on how to explain why baby gets to sleep in there and she doesn't?? It's the one thing so far that I can see her objecting to...
TIA!

Just say something like 'babies need to be close to their mummies all the time when they are tiny. He will wake up lots and need feeding lots and so he needs to sleep right next to mummy for a while, the same as you needed to when you were a baby'

Ditto what QoFE said, also that babies have smal tummies so need to feed lots at night, they also wake up for no reason and make a noise, so they need to be where mummy can hear so as not to wake her up. We had a new baby book which mentioned this (alongside a picture of a very tired and fed up toddler). DS1 didn't bat an eyelid, though did go through a stage of coming into our bed. We let him, provided he could stick to the bedsharing rules (no wriggling, no singing). He never could, so got taken back to bed, gently but firmly.

thanks, i will try that tactic. She does like her sleep, so the thing of baby not waking her up might work - fingers crossed!

ds1 was 2.8yrs when dc3 arrived and i didn't explain anything other than baby is nearly ready to come out of my tummy! i find it can confuse matters trying to come up with a toddler friendly reason to a lot of things and have only really needed to do it if/when he is struggling to accept something (giving up dummy!). if he's not happy about something then i try and explain why to help him understand but all other times i just say what is happening and that's that. if he had asked me why baby is in our room i would say 'you were in the cot in our room when you were a tiny baby but now you're older/bigger and sleep in your new bed in your own room' he seems quite happy to accept that he used to do certain things (dummy, nappys, sleep in a cot) but now he's older so his little brothers can still do them but he doesn't.