You're very good, and can only get better. I had an art teacher that taught me to always do my art in something that CANNOT be erased....that you can NEVER make a mistake. Truth be told, he was right. To this day, I always draw in pen or paint, so that nothing can ever be erased....some of my worst "errors" have become the best parts of my pictures.
Also, save everything that you have done.......you'll love to look back at it and it will continue to make you want to create art! I keep mine in a closet in a portfolio bag-and I occassionally add pictures to it that I have done even though I'm married with 3 kids later.........these are one of the few things in life that you'll love to look back on and that will always make you smile.
Keep up the FANTASTIC job!!
Edited because my fingers aren't on the same page as my brain