HI, I'm anewbie here, please be nice to me,hehe..
I have some questions..
I want to be able to play piano solo for pop music, is it true that I have to learn classical before I learn Pop music?Is it possible to do these things autodidactly?
I've been playing for a year or so now, and I can play a lot of pop music. You'll need to know a bunch of chord types to read lead sheet, but you'll learn these as you go. I started with classical (And still play classical). It really helps with reading proficiency, but I don't think it's essential.
One thing that has helped me a lot is registering on the mailing list at
https://www.betterpiano.com. There's a great PDF that you'll get in your inbox after you've registered called Instant Noodles for Piano. Chapter two has methods for pop improvisation, along with a couple of examples (One for beginners, and one for advanced students). Improvisation is a surefire way to improve your overall proficiency level.
That website has been a great help to me personally, so I thought I'd mention it. I'd most definitely recommend it to beginner/ intermediate level students, as you'll get frequent emails with advice and methods for improvisation. Advanced students will get something out of it, too. Personally, as I don't have a teacher, this resource has been extremely beneficial.