the world's fastest beating

Hello and welcome to TSF!

I like "makes my heart the world's fastest beating" it's different and quirky - something new and memorable.

You've noted that you don't really know how to divide songs, and that's probably the thing you need to look at first: structure. Without worrying too much about labels, just think of songs as having parts that are musically the same, like verses and the chorus. A chorus is (often) repeated verbatim, whereas verses will differ lyrically, but have the same music. Your chorus doesn't seem to repeat at all. So you need to make a decision: do you want a chorus or not? If it's a chorus, then make it repeat (you can just insert "chorus" later in the lyric if you've already set out once earlier what it is). If not, then you have another verse. All your verses are going to need to fit into the same musical slot and that means they should look alike in terms of how many lines are in each verse, and the length of the lines across verses. Eg line 1 in verse 1 should be about the same length as line 1 in verse 2, though within the same verse it may differ from lines 2, 3 or 4. And sometimes for variety you want a part that is musically completely different to everything else. This is often labelled as a Bridge. If you can look at a lyric and just by visually scanning it work out which parts are set to the same music, then you probably have a good structure to work with.

In terms of rhyming, there's no single best rhyming scheme, but be consistent. For example if your verses rhyme on lines 2 and 4, make sure they always rhyme on those lines in every verse. But you can choose to vary that between different musical parts, so the chorus might use a different rhyming pattern (maybe all four lines rhyme there) and that will sound fine.