When I wrote the first album I often found myself looking at 7 minute songs trying to cope with losing big chunks of the song in order to cut it down to 4 and a half minutes (at least).
I never think of how long my poems are but songwriting is different. The fun of writing a song is the various techniques at your disposal to convey an emotion or tell a story. You not only have the words and rhythm but you also have tempo, volume, melody, harmony, instrumentation, and any combination of these things to create emotions. Ironically one of the most precious and impactful tool within a song can be silence.
The main goal is to understand what you want to communicate and use some techniques that conjures up those feelings in you. I still have to remind myself that words are sometimes overrated.