Hey, I'm 16. I started reading books on spirituality at around 14 and I'm going through the same things as you right now. If you believe in a universal source, then ask for guidance humbly and it will come to you.
You don't need religion to access your spirit. You don't really need a spiritual leader, but whatever floats your boat. You have whatever it is you're looking for in you, you just gotta 'tune into it'. As some say, you're not a human being having a spiritual experience, you are a spiritual being having a human experience.
Most spirituality books will talk about the same things: forgiving others, becoming detached from material/earthly things and emotions, letting go of the ego, go out in nature, meditate, surrending to It (God, the Goddess, Him, Her, the Tao, the Universal Creator), trusting it, being silent enough to listen to your instinct, being humble, stuff like that. My advice is to breathe, chillax, shuffle your schedule to give yourself a couple hours, and meditate or pray to whatever you believe in for answers in a quiet, relaxed environment. But you have to keep in mind that the best you can do at all times is to just be a good person to everyone.
As for the vegetarian thing... it's great to go to a veggie restaurant every now and then for me. Jamaican spicy food is so invigorating
But, you don't have to avoid meat. As a growing girl, you need your nutrition and if you're more comfortable with meat, by all means, go ahead. Just start transitioning to healthier, nutritious food as you move away from junk/excessively processed food. If you eat nothing but watermelon for 2 days, McDonald's will taste DISGUSTING. I wasn't surprised, but I was surprised. You know?