You can try all of the style courses at the same time if you want.  I would encourage you to focus on one at a time.  If you like rock the most, then start there.  All of the concepts of notes, scales, chords & rhythm are the same on any guitar.   But there can be considerable differences in physical technique when switching to electric guitar to playing rock (& some blues):  picking techniques, bending, articulations like hammer-ons, pull-offs.  Getting started on electric as soon as possible will definitely be beneficial.

Hope that helps!