You can play by ear or you can read. Or you can do both. You can start playing in a band even if you can barely play - it just won't be a very good band. There is no substitute for playing with live humans, so find some other similarly skilled players and play. At the same time, get lessons.
There is no right or wrong way to become a musician. I do however have strong opinions, an my 13 year old son is getting the "fruits" of my approach. He has been taking piano (mostly pop songs - he digs The Beatles) for a few years, and has been studying drums for almost a year. On both he started reading from day one (I insisted) but he prefers to learn by ear and memorize. He is teaching himself guitar with some help from me (I won't give him proper lessons, and I'm only willing to pay for 2 different instruments at a time). At any rate, here are a few things I suggest:
1. Study piano. It is the "mother" instrument, and gives you insight into a lot of the basics of music. You can play any style of music on the piano, and by learning to read on piano you learn both treble and bass clefs. Even if you don't stick with it, a year of studying piano is worth it in the long run.
2. Study whatever other instrument you want. I recommend learning to read music and learning by ear - both will serve you well down the road.
3. There is no need to focus on only one instrument. You can have one be your main instrument, but knowing different instruments makes you better on your main instrument. I am primarily a bass player these days, but I've been playing guitar for 40 years, am so-so on keyboard, and can play drums in a pinch. Knowing guitar helps my bass playing in a variety of ways, as do both piano and drums. But find the instrument that really speaks to you. For me I "discovered" bass after playing guitar for 20 years. I found that I really liked the bridging of rhythm and melody. Plus guitarists are a dime a dozen
4. Practice, practice, practice. And play with other people often. I drag my son to some of the pro bono nursing home gigs I do. He plays cajon, and he'll thank me later when he wants to have a band with his friends and already understand the dynamics that take place when humans play music together.
5. Learn to read, have a good attitude, show up on time, and have good meter. The last one takes a lot of work, but is worth it. Guys who can do all of those things will gig often.