Im thinking about joining the army?

Ok, im 18 left school 2 years a go with terrible grades. I have had a tough up bringing, had to learn to put up with a lot of arguments, shouting and violence growing up. I Wanted to work for the council as a countryside warden so i went to college to try and do a course that may help me get there, they wouldnt let me go on it as my grades were low so i went on a lower one that was supposed to get me on to the higher one, once i had finally completed this they still wouldnt let me do it. So i went to a different college and studied mechanical engineering whilst working part time in mcdonalds, the course was nothing like engineering, let me down a lot and i got very fed up and stressed of the people/tutors there so i dropped out. I now work full time in mcdonalds. This isnt where i am supposed to be, it dosent feel right and i can do so much better. Im very fit and strong minded. Im not scared of much. I love adrenaline and being pushed to better myself. I love camping, getting dirty. I love all the things that come with the army. Im thinking about joining some time soon. Does anyone recommend it? I need something challenging and something to focus on, i also need to get out of this house as the abuse continues. My parents are alcoholics. i never see my farther who lives 200 miles away. I am sick of life at the age of 18. Its like an escape ? Do you think im making a good decision here? thankyou. And if you are in the army explain what you think of it? thank you!