Sounds like you have four challenges ahead of you.
Mastering your instrument, so you can perform. Whether it's your voice or your hands, it is going to take thousands of hours of training and practice so your body creates what your imagination hears. Master the Hanon hour of exercises then the Jazz Hanon so you don't think about your fingers, just the music.
Learning song writing, and the music theory that lets you document and improve upon it. The "Sodajerker on Songwriting" podcast is two professional songwriters from Liverpool interviewing songwriting luminaries about theIt craft; a remarkably good listen. I rely on the Hal Leonard Pocket Music Theory to fill in holes in my basic knowledge. Learn jazz theory because their whole academic universe is as practical and rigorous as for classical composition but made for songwriting.
Learning production well enough that you can make demos sound great. Pretty sure there's a Music Production for Dummies book. Recording, editing are straightforward; improving your performance in post is an art.
As Anca said, you also have to master the business. Licensing, IP protection, distribution, online merchandising, fan and community management, small business accounting, tour/gig booking, etc. San Francisco is not a music publishing capital like L.A. or Nashville; consider moving to where baristas have songwriters as heroes instead of tech entrepreneurs? Live among those who share your dream. Work among those from whom you'll learn the business.
But the best advice I've received as a writer is to write. Write a whole song — lyrics and music — every day. For a year. Each month look back at what you wrote and critique yourself, get better. Just write.
Break a leg, Adam.