starting to play piano...?

I am a beginner who alwys had a huge passion for music and people have alwys told me i have "musical" ears, could pick up tones very quickly, and looooooooooove singing!!! I have been thinking for awhile about taking it to the next step and learning to play an instrument... When I was little (1st grade) someone taught me how to play a tiny song on the piano and I loved the feeling of this instrument! So after much thought I decided to buy a piano keyboard and teach myself how to play!!! The keyboard will be arriving soon so i am getting prepared and searching up info as much as i can till it comes... Do u think it's really hard to learn it? how long will it be before i can be ok or descent in playing? I am more than willing to prac everyday an hr. or two... I heard its hard playing with both hands( the song that i was taught required one hand only) is it really that hard???? Any advices please??? Oh btw I barely turned 17 yrs old(is that too old?) and am a left handed( is that a good thing or bad?) Finally i found two very good resources of teaching on youtube.com (any other suggestions?)...Thanx!!! :) Please any advice would reaallly help because i am completely beginner at this and am reallly interested in this subject so please help me as much as u can and give me advices that i will be honored to try to achieve. thanx for reading! :)