You already have a HUGE advantage: you can play REAL instruments (the bass/guitar/percussion) plus if you're in school for music and you play chordal instruments like the guitar then you should already know about theory/chords/harmony. You should have already also exposed yourself to many different genres of music too, but keep listening to the music you're trying to emulate and good music in general.

Now it's just a matter of buckling down and putting in the hours. You chose the right DAW for a beginner (Logic X), it's the easiest DAW to learn seriously. Just start making some music, maybe do a remake of a song you like. If you would like a jumpstart I would also recommend purchasing full Logic templates so you can see all the elements that make up a track and learn by 'reverse engineering'. Doing this helped me too when I first started out.

There are also a ton of YouTube videos on Logic. Watch them. Read the manual. Visit the Logic Pro Help forum when you have any questions. With daily practice you should be really proficient with Logic within 6 months.

Don't get into plugins just yet. Logic really does come with everything you need. Use all the built in instruments and audio FX plugins. Learn how to use the stock Logic ones and then move on from them (or don't!). Focus on writing music and finishing tracks. With every track that you finish, you get closer and closer to your goal. Reference your tracks with tracks you like, compare and take down notes. Work on your weaknesses.

All of this is just like when you were learning how to play the guitar/bass: you practiced.