IB Diploma Vs Certificate for Pepperdine

<p>As an incoming junior, i'm moving to a new school that only has IB. I'm absolutely unfamiliar with how IB works.
My cumulative gpa as of now is 3.78 and I'm really hoping to get into Pepperdine
I'm just concerned that my gpa will drop if I go for the diploma. Is the diploma all that significant? or should I just be safe and save my gpa with the certificate?
Here are my list of classes for Junior Year:
Choir 1
Choir 2
IB Biology (SL)
IB Math (SL)
IB English (SL)
Normal US History
Spanish 4</p>

<p>Also,
I'm involved with Key Club, Interact Club, Church Worship Team, Two Choirs, Cross Country, Track and a job at a children's learning center. If that says anything about my time management.</p>