Here in the U.S., the folks living under the bridge downtown aren't all old alcoholics, drug addicts and other societal cast-offs. Many are, or were, youngsters that "left home" for problems that were, essentially, solvable. Don't apply a long term solution to a short term problem...
You don't say whether you're a boy or girl, but it doesn't really matter... life out there alone is not something you can even begin to imagine... and it's not pretty.
(You might get more responses suited for your needs in the "Family" section).