Maybe (and I've not long had my 5th so not being patronising) you feel a more sensitive about it with lugging a huge belly about and no doubt feeling tired and maybe a bit anxious about things.
Perhaps she could show her affection by making you a cup of tea, bit more grown up for her, they do tend to start rejecting cuddles as they reach the teenage years, so it may just be that being pregnant has moved that time forward a bit. In her eyes saying no to a cuddle may be her way of showing you she's being all grown up now.
Once the babies born get her involved as much as possible, my 11 year old feeds, changes and baths the baby, with supervision off course, but they are capable of a lot so let her do as much as she wants to to build a really good bond with the baby, but don't push her to do things she doesn't want to or expect her to feel the way you do about the baby and also keep times by for her, she's had you for 10 years so a bit of jealousy is natural.
Go and put your feet up and enjoy the last few days of peace and quiet!