>>1192436>Folding saw of bowsaw, cheap mora, snacks, warm (non cotton) clothes, tarp, rope, single walled metal water bottle, matchesDo not listen to this guy, you don't need half this shit.
Just dress properly, but use clothes you already have, and start going on day hikes. From there you will get a better knowledge about your environment, what you enjoy doing /out/ and tailor your shit from there. Your sneakers will do just fine and there's nothing wrong with starting with a pair of blue jeans, for base layers wear something synthetic and if it's cool remember that layering is your best friend.
Always carry water and tell your parents or friends where you are going and when should they expect you to be back. Have fun.
Also read pic related, it's available free on the web.