Outside of super low key jamming, ALWAYS be playing with a metronome. Always.
In my opinion, being an instrumentalist these days is getting harder, as you are competing with a popular music industry that is moving more and more away from conventional instruments and instrumentalists. You've got to have the precision and reliability of a synth track running on a computer, because that is becoming the expectation. For your band to succeed, and for you to succeed, you need the whole package. High level musicality, understanding of music theory, being an entertainer, knowing your gear, network with people, have as many marketable skills outside of music as possible, being reliable, being adaptable, working hard...the list goes on and on. Suffice to say, what some others here have said, making a living off of music is extremely difficult.
Also, in my opinion, you sound a bit like me when I was younger. I was super into music. Classically trained violinist and singer. Picked up guitar largely on my own. Was determined to go to a music college to get a degree in music performance. I was in high school bands that I loved. I was in choirs. I was in orchestras. I did solo voice performances often.
My perspective changed when my parents decided it was time to level with me...they were pretty upfront about not wanting me to try to live that life. They convinced me to go to college, get a more applicable degree (I went into engineering), and to work full time with music as my after hours hobby. Maybe it's just me, but I couldn't be happier with where I'm at. I'm satisfied with my work, but it's just work. When I come home I can do all the stuff I want, because I can afford to have expensive hobbies. I spend a lot of time playing bass and being in a band, but I can still simply enjoy it because I don't depend on it for income. Hobbies are easily polluted with frustration and stress when you turn them into your job. At least for me, I'd rather my passion for music just be passion...something I do for fun.
And to make sure somebody mentions it...even high level pro musicians make absolutely awful money these days. I've talked to and head from several current top-tier musicians in the metal community, and they have a really hard time getting by. All the musicians in 3 of my favorite bands (TesseracT, Periphery, and Twelve Foot Ninja) are all pretty upfront that their bands don't make them any money, and in their earlier stages they were continually losing money. They all have to take breaks from your now and then to work a side job for cash, or to do some other project that will generate some income for them. I don't want to say they are unhappy, I'm just trying to say that they work much harder than most people, and they make very little money.
It may sound crude, and I don't want to get all Mike Rowe on you, but if you want to be do music but want to have a stable income and steady job that you can use to finance your hobby...learn how to be a welder, plummer, electrician, etc. If you can get an apprenticeship, within 4-5 years I'd confidently say you're yearly income will be than most of your idols have and will ever make.
I know as a young person us "oldies" talk too about money, and in the face of something you're super passionate about money seems like a stupid thing to worry about...but I think you'll find as you get a little older, a steady job with consistent income is really desirable.
I say/type these same things to all people who are interested in becoming "pros" at anything creative or performance based, so I'm not just picking on you. Same goes for all the people who want to be pro-gamers, pro-chefs, pro-athletes...etc on and on.