Given age difference, my friendship would be inappropriate. And you should be suspicious of any adult that contacts you. Don't accept their friendship if the age gap is more than a couple years. Just don't.
However, having dealt with a really rough life at a similar age (depression, later bi-polar; fucked up family; institutionalized), I want to offer you words of encouragement. I was / have been miserable and lonely at different stages in life and I want you to know that you can radically change your situation. It takes time and effort, but it can be done. Please don't give up. Good luck.
Any adults that see this and think you see an opportunity, fuck you. Leave this person alone.