Your GPA Might.... or it Might NOT change. There's too many variables. Not just whether you're taking IB classes, but the "School Profile" of your school. FWIW: My son had a 4.0 gpa with EVERY CLASS being IB for 4 years. 9-12 grade. He was always a 4.0gpa. The academy had his gpa listed as a 4.0. His school didn't weight classes; only class ranking. Yet; I've seen those with gpa's in schools that do rank, that were 4.8 or above, and they were readjusted by the academy to a 4.2 or similar. Too many variables.
One thing I will tell you: The points that you receive in your WCS: Are heavily weighted on WHAT CLASSES you took. In other words; you only see the GPA listed on your application. But the academics section of your WCS; which you don't get to see; includes what classes were available; what you took; what grades you got; class rank; SAT/ACT; etc... So in other words; don't worry about it if it stays where it is. They know you took IB, and they definitely know what IB is. You definitely received points for those classes. Best of luck to you. Mike.....