While girls *generally* can potty train sooner than boys, I still think 19 months is young if anything - most definitely NOT "old"!
My son didn't potty train till 4? (I forget now! wow) but I am glad I did not potty train even though I felt bad/wondered if I should work on potty training after we moved here when he was 3 and found some boys the same age or slightly younger that had potty trained. Reason I say that is because after being out with these other 'potty trained' boys I realized - they were potty trained to pee only, but they still pooped in their pants!! Eyuck. I'd far rather deal with poopy diapers than poopy underwear!!!
Also, you have a baby coming, I have no experience with this but have heard of young older siblings regressing when the baby is born.
Don't push. Dont make her grow up just because someone somewhere else thinks it is "old" or "time" or "everyone" else does it.
Follow your gut feelings, and let her ease into milestones. She has her own timetable. There is PLENTY of time for her to be pushed to progress at other people's pace once she enters school, let her grow up on her own timetable for now.
Also - when SHE is truly ready for potty training, it will be easy, quick, amazing, pleasurable. If you try to train her before she is ready, it will be a long hair-pulling frustrating experience. Each child has a "magic" date (magic because nothing works before then and it's totally top secret to everyone!) by when they can be potty trained. It may be 2, it may be 3, or it may be 4. Whatever you do before then, is just going to be that much longer of a potty training process. (I am sure some will disagree with me here and I have no science to back this up, it is just my personal theory but my point is - if you WANT the hassle of potty training, go right ahead. If you want to keep it short & sweet, wait till she's ready!)
Signs of readiness: When she can wake up in the morning dry. When she can make herself go pee (before a bath for example). When she can tell you (or you can tell by her physical behaviors) that she needs to go. And another consideration - when she can manage to pull down her clothes to sit on the potty.
If she is potty trained at 2 but still needs you for the next 2 years to go with her "right now" to the potty to help her get her pants off & on, hm. That's not my goal, independence is.