19 month old and pull ups

As the title says I have a 19 month old and she has been pulling at her pull up when she is naked besides that, she also put her hand in her pull-up twice now when it has poop in it then comes to me to clean her hands. She does have a potty training toilet and will sit on it but will not use the restroom in it. I am also 22 weeks pregnant. I am afraid if I do try to full on potty train her she will take a step backwards once her brother is here. I also know she is still pretty young to be potty trained. She doesn’t say a whole lot of words that are understandable just yet as well. I am looking for advice on anything to help me with her.