grammar - Using references to the present in past tense narrative

I am writing a Young Adult novel with narrative in the past tense however I want to include some words such as now, this, tonight, etc that indicate present but don't know if I can. However, I am reading many YA novels that do. For example,
"She lived in Seattle now." "Now, I didn't know what to think." "His appearance was so altered, now dressed in... ". "I was now in a boat.'"Tomorrow would be a nightmare." Should I remove all these references to the present to make the grammar correct. Or should I keep them as some authors are doing?