I'm writing a song for my band in and i want to know if this is sounds correct to you guys. First off, im self taught and don't completely have my head around the whole theory thing.

The song so far starts with me walking down D minor then going up the D minor triad and then down the E diminished triad. I've written out the guitar line as just Dm to C (Chords). After that I mess around in A Mixolydian while the guitar line plays Gm something (it consists of the 1,3b,4,5)

Does this make any sense theory wise?

Does it sound good musically? If yes, go ahead!

Theoretically, there's nothing really wrong with it. Playing in A (mixolydian or not) against a Gm could be a little atonal, but, so long as you're careful picking which notes you pause on, it could work just fine.