I haven't written very many poems or songs... but something I like to keep in mind (or kind of refer to?) is the rhythm of the words (the
Meter, I think it's officially called? Like the "iambic pentameter" that Shakespeare uses).
For instance, your first line reads something like:
"I looked into your eyes"
(de dum de dum de dum) (if "de" is weak" and "dum" is a strong syllable - if that makes any sense?!)
and your second line is:
"and saw straight away"
(de dum dum de dum)
So I noticed that straight away your second line
almost matches your first line, in stresses... so I might be tempted to add another syllable in there, maybe along the lines of: "and saw (that?) straight away", which would give you another "de dum de dum de dum" pattern. You can then re-use this pattern for other verses, occasionally varying it for dramatic effect.
I dunno if it all seems a bit weird, but it effects how the poem/song sounds when read out, I think
Also ... to be picky about grammar... some of your "your"s should probably be "you're"s - since they are contractions of "you are" (eg. "You're the only one" and "You're cool, funny, smart").
Very nice though, I especially like the second last verse
Good luck with it!