Hi Melly!
Glad to hear that all is well with the pregnancy and that you are a little more relaxed about everything.
If you feel that you are happy to continue and that you have the time and the patience, I would continue in a very low profile way. Don't pressure her at all (I'm sure you won't) continue to reward her with praise when she perfiorms and just ignore the accidents.
Is she able to say she wants the pot? My DD couldn't really say wee, but if left knickerless she would run to it and perform of her own accord. She could only say poo at 18 months and we never knew what was going to come!
I think it is a good idea for them to feel wet, so don't rush to change her pants etc, I used terry cloth pants from John Lewis which were very absorbent. When I trained DD, nappies weren't like todays, the best you could get were Peaudouce, then later Pampers came out, they used to reach her knees when wet!
Like Rhubarb, I found that she was dry at night a few times first of all. She would have a paddy pad in her nappy and I would have to change her at about 11pm or the cot would be soaked. I was so worried when I went to change her and it was dry at 11pm and then at 7,00am, I left her nappy off and rang the doctor at 9.00 as she hadn't wet for over 12 hours, whilst on the phone she let go of her bladder all over the kitchen floor!
She was reliably dry during the day at 16months, I left nappies on at night until 18 month and then just left them off to see if she wet, but she didn't.
I also had DS dry day and night at 18months, he just copied DD, (only a year apart) He was no problem, everyone said boys would be different and a lot harder work. My mother says she had us all dry at a year, but then don't all mothers! I have seen my Christening photos at 14 months and I am wearing knickers!
I think I was very lucky, but all the children I have looked after (like your Auntie) have all been dry before 2. I would say the average age is about 20 months.
The little boy I look after at the moment was dry day and night together at 22 months, he has never had a single accident, unbelievable but true, but big bro is nearly 5 and still needs a nappy at night.
With Aunties support and your family I'm sure you'll get there. When newbaby arrives, just remember to pot DD before you sit down to feed, or as I did, collect the pot, a drink, a biscuit and a book so you don't need to get up again. You can guarantee this is when she will ask!
I firmly believe in introducing the pot by the time they are walking, at bath time and first thing in the morning, it doesn't matter if they don't do anything, it's just getting used to the idea. Especially as some kids freak out at the idea! I find that early walkers are ready sooner than late walkers, must be something to do with coordination and development.
Good luck, you'll both be fine