Imported skills beside matlab for developing engineering application [on hold]

Recently I graduated from college, math was my major. My first employment will be in some engineering company. I will support engineers to solve engineering Problems as well as developing a GUI for there application. Both will be done in matlab. Besides picking up some Matlab skills I also would like the refresh my programming skills before I start. In college I took a courses on C and Java. Now, my question is: What would be better so start with? In my opinion I should start with C because I think for developing engineering application object orientated Programming (=OOP) will most likely not occur. But I also read that one can do OOP stuff with matlab. Maybe It is import to know the basics there as well. What do you think would be better to start with?