I highly recommend checking out Youtube videos before beginning play, and in particular, a series of videos by PurgeGamers and his Welcome to Dota, You Suck videos.
Dota is notoriously difficult to start playing and the community in general is not very friendly. However I have never played a video game for 5 years straight and never gotten bored, nor play a game that has made me a better person as a whole. If you stick with it, you may find the same love and enjoyment that thousands across the globe have as well, and with The International 7 around the corner, there is no better time for watching professional Dota and to figure out the meta (Which heroes are strong right now).
I wish you the best of luck.