Sibling jealousy

I have an 11 year old Edie. It was just me and her for a really long time since I had her at 13 and her dad walked out on us. Last year I started dating a new guy Edie was ok with it just took some adjustments. I’m now expecting a new daughter in December and I can tell it’s bothering Edie how much time is now devoted to this new baby. It went from 11 years with just her and now she’s having to share and adjust again in a short amount of time.

I want to support her and now that I’m out of work for the summer (I’m a teacher) and she’s just left her last year of primary I want to make this summer about her and make it special. I just want to make sure the air is cleared and she is happy with the arrangement before her little sister is born.