How does my photography look?

I have a huge passion for photography and I know that I later want to pursue it as a career. I'm 15 years old now and I have been into photography for about a year and a half.
I'm looking for second opinions on my photographs, advice, tips, anything you can give me. Anything that will make me improve as a photographer. Or even just overall what you think about my photographs, that would be great.
All of these photos were taken with a Nikon D3100 and lens is a 18-55mm that came with the camera. I'm hoping to upgrade to a 50mm f\1.4 lens on my birthday.
Anyways any opinions would be GREAT. Thanks so much.

I think they look very nice, i really like the rich colours. The first and third would be my favourites.

You definitely have an eye for photography. Well done, but never stop trying to improve! Think about your favourite areas and look at photographers in them areas and always strive to be the best.