"Don't you hide your pretty face
Behind that auburn hair
Been drowning for so long
Finally coming up for air."
"Because behind dark clouds
The sun, it still shines."
"Painted the walls
With thoughts and words you long to say"
I enjoyed the imagery in these lines. Drowning in one's own hair particularly, is a very compelling metaphor for shyness. It seems to encapsulate both the weakness and despair it can often bring along with the overtones of panic that come with attention. It is also one I haven't heard before, although others might have.
The language is sometimes confusing however, for example,
"Up in your room
Alone, you've locked away"
Perhaps you meant to use "You're" instead or "You've" or some similar minor spelling error? Otherwise this is not a complete sentence, you have no subject. Either she locked away something or she is herself the thing locked away.
Also, "Been drowning for so long/Finally coming up for air". Have you intentionally dropped the subject from these two lines for melodic purposes? Should it not be, "You've been drowning for so long/But you're finally coming up for air" or something similar? I had to re-read the lines to make sure I didn't miss something.
The last verse does not seem as well put together as the rest of the song either. It feels like a jumble of semi-related ideas that don't transition well and suffers from the same kind of confusing language as above. The flower in a darkened room not blooming is another good bit though.
The song also comes off to me as a little arrogant and maybe a bit controlling right from the opening line of, "Girl it's time you learned". I interpreted the song as a whole as "Hey girl you're super shy but you're also awesome and i'm going to try and pull you out of your shell". Was that the intent or not? Maybe i'm missing it. I admit I might just be oversensitive but who are you to tell her how she should live or whats best for her or what she should value most? While it's clear she's shy, she also appears to be quite introspective(IE the poetry stuff) which offers a whole world the narrator seems to dismiss as less valuable. I don't think you've done enough to show why being shy is something worthy of changing. Especially when you end the song with a contradictory message to the beginning. I read, "If only she'd leave her shoegazers chamber" and "We'll lock the door/A shoegazer for all eternity." as seemingly contradictory. Considering the narrator carries both messages, what exactly are you trying to say here?
I think there are plenty or great ideas and lines in here and the overall the idea is a good one but it's a bit confusing at times and the main message by the end is unclear. Some parts are not as well written as they could be but it's well worth the work in maybe rewriting some bits. I did enjoy reading it though, well done.