If you do copy, always state that you referenced, and give credit to the artist. This just shows the rightful respect to the artist you've learned off of. :) Just be wary of those that don't like to be copied, with given credit or not, if you choose a random person off of an art community or something.
Determination along with practice will take you a long way. Take critiques with grace, and don't constantly bash yourself. You'll just kill your motivation if you do. A few people said it, but I'll state it again, making simple 3D is a good way to start. Possibly study up on a bit of perspective while you're at it. Once you've gotten use to all that move on to more complex objects (fruit or random objects around the house work), then anatomy. It's a slow process with a lot of hard work, but it's really worth it if you are truly serious about becoming an artist.
Best of luck to ya! I'm sure you'll do great! :D