I want to put in my 2 cents.
Amashi, you have a great potential as an artist, you have a sense of humor, you have your style and ideas, just keep drawing, you are only 13 years old! You have a whole life ahead of you! Man, I'm almost 29, I wish I was as good as you in digital painting when I was 13.
And remember that art is subjective. Ask for honest opinion, of course, but not only one person and first ask YOURSELF if you like what you did. And most importantly, ask yourself if what you do makes you happy, if you like doing what you are doing.
Just keep practicing and you gonna get better and better.