Totally disagree with you, Jess
Just because you don't know any of the fancy words to describe music theory doesn't mean you don't know any music theory. The fact that you can throw a chord sequence together and write a melody to it is proof of this.
The idea that finding your way
in spite of a lack of musical knowledge is somehow more magical is simply a myth in my opinion. The music theory deniers who write great songs tend to have a great grasp of many of the basic principles of music theory. They just picked them up without any formal training and without the context of the posh words.
So, Sing4me88, my answer to you is: yes, technically. But there really is no replacement for learning to play an instrument, even to a basic level. You can write really great songs just playing simple chords on the piano or guitar.
Also, I think it's worth pointing out that a lyric & melody on its own isn't
quite a song yet. Without the harmony (chord sequence) that underpins your song, there's an important element missing. Choice of chords/ harmony can make a
massive difference to the emotional flavour of a song, and could potentially make or break a good lyric and melody.
Maybe not the answer you're looking for, but I hope it helps.
For the record, music theory is one of the most
interesting things I can think of!