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!