Not sure what to tell you about whether this is the right time for your daughter, or not (with a new baby coming and all) but I can tell you I trained my two daughters at the same time last Thanksgiving weekend - went cold turkey for both day and nightime diapers and never used Pull-ups. My youngest was 3.5 months shy of her third birthday at the time (older one was almost 4, but she has Down syndrome, so I'd always planned on training them together when the younger one was ready).
We did have some accidents at night, but not many and they have stopped for the most part (my younger one might have had one two months ago, but that was VERY isolated and again a long time since the previous incident). Here's my biggest tip for you: plan to buy the cheapest mattress cover you can find and purchase several of them. I think I paid around $5 for a cheap, fitted cover at Target. Layer the cover and then a fitted sheet, then another cover and another fitted sheet and if you want to do more layers than that - go right ahead. At night if (when) she has an accident.... it is very easy to just strip off the top sheet and cover and you are all set to put her right back to bed!
Of course you should do as the other moms have said and limit her liquid intake after supper at night. Also, having her go before bed, and before you go to bed is how I did it, and that helps a lot. I also read to wake the child about 30 minutes before she normally gets up and have her go then as well. She'll get the hang of it!! By the way, my girls also didn't really get out of bed, and certainly didn't leave their room at night, so we had a little potty chair in their room they could go in if they woke up and we weren't around.
Good luck with this! I'm sure it'll go fine! :-)