I don't have any answers, just wanted to wish you good luck and to not give up & have fun going for it!
I am a late creative bloomer too. I plan on launching an online visual art business that I have been working on for several years now. I will be 49 this year and feel I have been waiting all my life to do what I "really" want to do.
I hope someone responds here, but if not - I have always been a big proponent of self help books on the subject. They are a place to start, at least. Amazon has a lot of honest reviews & the feedback can help you decide what books are best for your needs.
Try & learn as much as possible before signing any contracts with anyone, that much I can say for sure. Get info straight from the horses mouth - call the official copyright agency in your country & get as much info as possible so you can properly protect your work before you start sharing to the public. Don't let anyone steal your stuff!
I also like to read books on creativity that inspire. Like "The Artists Way" by Julia Cameron. It helps to motivate me & clear creative blocks. Books by Barbara Sher are good to, she helps with creative career solutions & has lots of online support groups.
As you gather more info on your journey, perhaps you can find an online discussion group of like minded song writers or maybe even us "meet up" and connect with others in real life.
Enjoy your exciting new journey, I'm routing for you
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Wherever you go, no matter what the weather,
always bring your own sunshine!
~Anthony J. D'Angelo, The College Blue Book
You can't stop the waves, but you can learn how to surf!
~Jon Kabat-Zinn