Don't worry about average, but DO worry about:
Are you driving the ball? What percentage of hittable pitches that you swing at (and you should be swinging at most of them) are you hitting hard?
If you have 23 walks it means that you are patient and selective at the plate, which I think is part of being a good hitter.
But I think you also have to know what your perfect pitch is and be able to hammer it, and conversely, ,know what your weakness is (the pitch you sometimes get fooled on or swing when you shouldn't) and learn to recognize it and lay off it.
A .307 average at 14 year old doesn't mean much, especially if the question is how good of a hitter will you be at 17.
But if I was your dad (and I AM the dad of a 14 year old) I would be looking at your mechanics, not so much your average.