Step daughter isn't excited 💔

I feel like I have a very good relationship with my step daughter. Daddy works a lot so it's often times just me and her. She's 8. She's unaware of the difficulty we have had getting pregnant (4 miscarriages to date of 5 years). When we told her last week she went home and the first thing she told her mom was that she didn't want me to have a baby because I would spend all my time with it instead of her. I know this is a learned behavior from her "not so great" mom who has two younger children and I know that she felt tossed aside alot. We plan on having her come to atleast one ultrasound appointment because I feel like she will feel more involved but do you ladies have any suggestions on other ideas that I can do to make her feel less anxious about having to share us? She doesn't get a lot of attention at home and being the only child in our home has kinda been her vacation from her siblings and I just really want this to be as smooth of a transition as possible. Please help!