I can't harsh on you too bad, particularly if you are 13. Truly some real promise in composition for someone so new to photography. I'm not going to get too far into the details on individual pics. Instead, my overall impression: you need to really think about contrast.
The jump from color to black and white can be hard to perfect because you have consciously think about the scale of light to dark without color. Working with color is innate, because you see the contrast in color without thinking about it. Success with black and white shots requires conscious thought about contrast. Black and white does change the mood, but what exactly is the mood that you are creating? Most of the pics in those links were very muted in gray. It can be right in some shots, but generally you need contrast to define the shapes.
That said, contrast can also ruin some shots. It's a double edged sword. Still though, I'm impressed with the natural composition in someone so young. Keep shooting bro!