I will have to agree with everyone, Dota 2 is one of the hardest games out there. But in my honest opinion its one of the most rewarding too ! I cant quite describe the feeling of having a huge comeback with your buddies or the feeling of hitting a 5 man black hole ,rp or any skill related to that. If you actually decide to get into dota 2 i suggest watching dota cinema videos. They have a playlist with ALL the hero introductions which can help out a ton ! Purge has also very educational videos and u should watch as many as u can !
Firstly start playing with bots. Get to understand the basics of the game, you didnt mention if u have any experience with other mobas but if u dont , there are a lot of things u need to get used to , like : where your hero is, where u should go in the beggining of the game how to last hit etc etc.
To conclude Dota 2 is an amazingly hard game with a huge learning curve , however when u forget about all the retards and the russians Dota 2 IS the most rewarding game i've played and the ammount of SATISFACTION it can offer is unique !
If you decide to start dota 2 you can definetely hit me up if u play in the EU or play in EU times