My first band was when I was 17 and I was the vocalist/front man in a Black Sabbath cover band. I actually had about 6 years of vocal training and experience in vocal groups with good vocal habits and I could sight read and was musically literate. Plus, I sounded just like Ozzy when mimicking his style.
But our band had an impossible time finding and keeping a bassist. I think we went through about 6 bassists in our 1st year. Made it really hard to book gigs and we sounded terrible with sucky Geezers.
So, one day the guitarist and drummer came up to me and presented me an electric bass, saying that since I wasn't doing anything with my hands while on stage, I might as well make myself useful and learn how to play bass. They had found a beat up JB Player from somewhere and told me to get a bass amp to go with it and get busy learning how to be Geezer Butler.
I responded that I had never touched a music instrument in my life and also I was left handed, and this was a right handed bass. The guitarist said "**** you and your ******* left handedness. Learn how to play the bass or you're out of the band."
He was smiling as he said it, but he wasn't kidding.
So, I started learning on my own, but this was at a time when I was just signing up for a semester at community college. I discovered there was a course called "Rock group ensemble", where the idea was to teach students how to perform in a rock cover group.
I took the class and it was a huge help, considering I wouldn't have known what to work on or how to practice just on my own. There were about 18 students in the class. Two drummers, three keys, a couple of horns, and probably 10 guitarists and as many vocalists. I was the only chump with a bass.
I made good progress, but after the semester, I was hoping for more instruction. Fortunately, the teacher of the class informed me that there was another class just newly formed for the new semester called "Small jazz combo" and they would need a bass player or they would have to cancel the class. I signed up for that and learned how to play jazz, including reading charts and improvising different kinds of basslines.
I was extremely lucky to be a part of it, because the other guys in the group (it was a 6 piece, including the teacher) were all very experienced and very talented. They knew that I was a total noob but were all willing to go out of their way to teach me how to play, because without me, they had no band.
Fron the first day we had an agreement. They would accomodate my beginner status and work with me to help me improve, but I had to promise to put in 10 solid hours per week of practice on my own and do all the homework they assigned to me.
I jumped at the chance. I was able to take advantage of the opportunity to learn jazz from some talented players, plus the teacher of the course actually donated 2 or 3 hours of his time every week to giving me private lessons.
It went extremely well and the band members told me it was obvious that I was putting in the work and holding up my end of the bargain and were pleased with my performance at the public concert we put on for our final grade.
I repeated the course the following semester and that experience got me into the habit of playing bass and practicing 10 to 12 hours every week without fail. Thirty five years later, and I still have the same work ethic.
Looking back on that one year I can't help but think if I hadn't been coerced into learning the bass as a rank amateur and then given the opportunity to learn from some excellent teachers on a strict timetable, I might have gotten bored and given up, not having discovered a passion for bass playing.