Well, my parents just suggested I might like it and i was like 'yeah, whatever' being 8 years old at the time and not really knowing what I was getting into.
Then I just carried on and got more and more keen as I got better.
There's two approaches to playing instruments if you are serious about it. Most players have a bit of both, but one tends to dominate.
One is the classical approach- get the sheet music, learn to read it properly from the beginning and spend weeks learning each piece until it is perfect. The result is you sound fantastic and can get into orchestras or musical theatre bands, but you are essentially an athlete who is a slave to what the composer wrote.
The second approach is the popular/jazz approach: learn to play chords, and just develop your playing from chords more and more until you have a complete arrangement. Then learn to improvise melody and solos
.
The upside of this you understand the music a lot better and can alter it to however you want, and write music. The downside is you will never, ever, ever come close to the technical ability of a classical player. If you take the classical approach, it doesn't take very long to learn popular music better than any pop musician could. If you're a pop musician, it's really hard to become a classical musician.
There's also a third approach where you go on youtube and watch the notes people are playing and copy them. It's really really slow and you waste all your time trying to remember the notes, but the upside is anyone can do it instantly and it doesn't take as long as trying to read music for the first time.