Is it hard to learn guitar by oneself? Does it need a lot of time?

i taught myself guitar without any books or things like that but working around school homework and other things in my life it only took me a few weeks to start playing well it's been like 2-3 months and one of the best things ive found is martyzsongs ( a href="http://www.youtube.com/user/martyzsongs" rel="nofollow"http://www.youtube.com/user/martyzsongs/a ) has alot of great tutorials as far as learning chords and songs and picking.