Great general advice, Casey, although it's hard to tell without hearing the actual song. There are plenty of three-minute songs that feel too long by half, and a fair number of four-minute songs that are just right for what they do. But 124 BPM feels more like mid-tempo than ballad, IMO.
Without actually hearing the song, and what you have to say and how you say it, it's hard to comment on the length, but the tempo is quick enough to cut both the intro and the instrument solo in half (to 4 and 8 bars, respectively). Same thing with the bridge, depending again on what you have to say.
With regard to structure, the type you choose depends. The most COMMON song structures and the structure with the most hits are often different and tend to change over time. According to Ralph Murphy (who analyzes the hit songs every year), in 1999:
"Your best shot for getting a #1 (country) record (was) to write:
mid- to up-tempo
romantic/humorous or sad/heartfelt theme
4/4 time
contemporary pop/country style
story or conversation
1st person or 2nd person
3rd form: Verse-(Verse Opt.)-Chorus-Verse-Chorus-Bridge-Instrument-Chorus-Out
linear melody with a story to a soaring chorus
13 second intro"
source:
https://www.ascap.com/music-career/arti ... w/murphy16
But in 2016, "if you want to write a #1 Pop Billboard Chart record......and remember these were the #1 hits of last year. This is the consumer speaking, not me!
of the 9 #1 songs on the Billboard Hot 100,
Five were 4th form: verse, verse, pre-chorus, chorus, verse, pre-chorus chorus, middle 8, chorus...out). That structure seems to fit the listeners expectation in Pop.
Three were third form: v, chorus, v, chorus, middle 8/breakdown/instrumental, chorus out...).
Let's take a look at Justin Beiber. He has a 14 second intro, and a very European approach as he starts with the chorus, but it's also 125 BPM so it's trying to be all things to all people by adding in radio as well as dance.
Adele also mixed forms....the very cool 5th form (a,a,b,a) is mixed in with the 4th form to really maximize the title "Hello". After the obligatory two verses starting with the title there is a small prechorus/bridge/lift before what should have been viewed as a bridge....it's in this case treated as a chorus.
There is also a "breakdown" or "middle eight" which uses the word "anymore" which is the last word of the bridge/ chorus just to further the illusion of 4th form.
Have an approximately 9 second intro (that's factoring in Taylor Swifts "zero start" and dividing by the total number of songs on the Chart).
Use the pronoun "you" within 21 seconds or sooner.
Use detail to invite the listener in...and tell them how good/bad that "you" is.
As all the 9 #1s are aimed at radio, whether streaming or not, dancing or not, get to the first use of title in one minute or less and have a dead end.
If you're aiming at under 100 BPM, all of them were between 80 and 86 BPM.
.....and that gender issue, I won't touch at all... "
Source:
https://murphyslawsofsongwriting.com/1- ... harts-2016
So it's complicated. The more 'common' your structure is, the more closely it conforms to listener's expectations, the more likely more listeners will 'get' it. On the other hand, there's more than one way to structure a song, and that's determined in part by what you have to say and by the genre you're writing in. I would encourage you to try all the common song forms, and see which ones you prefer. After all, you have to learn the "rules" before you learn how (and when) to break them.
Best of luck, whatever structure you choose.
Casey