What Lisa said is true. It will no doubt be harder for her than for you, especially if she wasn't the one who wanted the divorce and/or hasn't yet met anyone else. But if she's been cordial so far, she'll probably continue to be so. If she's mature, she won't want to poison her child against dad's new wife. You're off to a really good start, it sounds. I'll give you an example of the opposite:
Many moons ago, I had a long-term, ultimately live-in relationship with a man who was legally separated and waiting to get a divorce when we met. He and his wife didn't love each other when they got married; her parents pressured them into getting married after she got pregnant. She filed for divorce after they'd both cheated on each other within a year of getting married (there was no sadness about the divorce on either side), and his daughter was two years old when he and I met. Regardless, the ex-wife was very hostile toward me from minute one and throughout my three-and-a-half year relationship with her ex-husband (my boyfriend said she was irrationally jealous of me--not because of her feelings for him, but because she thought I was prettier and smarter than she was--we're talking petty stuff here), although she was living with another man within months after they separated. It made matters worse that their daughter really loved me. Visitation-wise, he had his daughter every other weekend, alternate holidays, a month in the summer, etc., so I was surrogate mom then (and whenever we picked her up from her mom's, she'd have drawn me a picture or made me something). His daughter, as her vocabulary improved with age, would innocently ask me why her mom said bad things about me (I was stunned that the ex would manipulate a child that way). I was a vegetarian, and my boyfriend ate vegetarian meals when we ate together. We used to get veggie burgers that his daughter (a big meat-lover) really liked. Markus told his ex-wife that he was amazed how much their daughter loved veggie burgers, and sure enough, the next weekend we had her, she refused to eat them ("I don't like them--they're not real meat!"), as if a child normally would give that a second thought. In other words, his ex-wife had pulled one of dozens of childish stunts throughout the years.
Anyway, don't feel that you need to impress her, or live up to her standards. It would be cool (although unlikely) if you two ended up being good friends, but your husband might feel a bit uncomfortable at the prospect of your sharing notes.
Hope it's going well.
Suzanne