It's great, especially for a first song! I'd never have said it was your first if you didn't say that. I think that not only will your fiancee love it, but it will also be stuck in my head for quite some time.
Do you have the lyrics written out somewhere that you could paste in here? My computer's not handling Youtube well today.
Sure, the lyrics are:

Light ash scours ‘cross the sea,
Makes the water taste salty
Dunes of peach are out of reach
A long way is my est’ry

On the horizon, dawn has broken
The sun it smiles, a rosso corsa
Strange shapes move and tessalate
I have found my est’ry

I wrote a song for you
Because you asked me to
I wrote a song for you
To say I love you
I wrote a song for you
To hear when I miss you
I wrote a song for you

Ice bergs dwell from deep within
The rippling tide which covers skin
Venus smiles a cheeky grin
I am with my est-ry


Tea rose plateaus sink and rise
Thoughts of castles in the mind
Roots of trees become entwined
I am with my est-ry

Thanks! What I did get from Youtube sounded good, but it was too skippy for me to get all the lyrics.

First two verses sound great, I like "rosso corsa" being worked in... I take it est'ry is short for estuary?

Chorus is cute, I hope she likes it!

Second two verses sound good as well, the only thing that sounds odd to me is "dwell from deep within" - "from deep within" sounds like it implies movement, while "dwell" doesn't. But I might be reading it wrong, and of course keep it if it's what you were going for!

I like it, keep it up!
She'll love it. I wanna point out that in the tags on the youtube video, you basically tagged everything involved expect for the word "guitar"

just found it funny
Your mother likes it ruff, Trebeck.
Wow, thanks for your comments everyone. Very encouraging to read! Much appreciated
That is a really good song.
But personally I'd prefer more rhymes. But that's just me and how I like my songs to be.

The voice kinda reminded me of Pink Floyd.