That is a fairly difficult question to answer. I've been interested in drawing on and off since before high school, but I don't think I made a conscious effort to improve until later in college (about 2003). Around 2008 or 2009 is where I began to draw regularly with less periods of idleness. That's about where my gallery begins with a few pieces from the "color with a mouse" era of the preceding years.
Even if this is "just Trixie," as you say, she's still so great and powerful that she need a massive fireworks display in the background. Trixie knows Trixie is the most magical unicorn, and the most apologetic, AND the most humble pony in all of Equestria...because Trixie said so.
I have to say that I really love this piece and I really believe that this is a great way of showcasing your artistic talents! The character design is done extremely well and everything from the line work to the textures is very highly refined! I also love the way that you seamlessly melded the lighting from the fireworks with the beautiful shading to add a gorgeous depth! The color work is also brilliant and I love the fact that you made the fireworks with neon color! Each facet of detail comes to glorious life and ties the piece together! This is a really fantastic piece and I would love to see more! Great work! Kind regards, Princess Luna