I think you might be looking at art with the wrong kind of mindset, my friend
If I were you, I wouldn't look at drawing and art as something that you're ready or not ready for. There's really no point where you're graced with the blessings of the universe to be an artist. It's a mindset, whether or not you're ready.
If by 'going into this field' you mean art and design, then the best time to 'get into it' is right now. Every day will be a learning experience and a stepping stone on an endless path. Personally, I'm about to graduate from a university with a BFA in graphic design. I still don't consider myself ready in several aspects, despite being ahead of the pack in many areas.
Do what you love. If drawing and studying anatomy are your interests, it's safe to consider yourself ready.
Whether or not you're "good" is an entirely different story. You have a lot of room to improve, but everybody does. Even the best out there never stop practicing. Get comfortable receiving critique because it's an artist's best tool. I suggest reading this article here for some insight.
alistapart dot com/article/design-criticism-creative-process
I just wanna point out too that this particular board can be an incredibly toxic environment to a beginning artist while simultaneously being a useful, readily accessible tool for critique. Don't just come here for input, create an FA account and ask for real critique. Ask your friends and family for honest feedback, maybe try and make friends with an established artist. You'd be surprised, some of us thoroughly enjoy teaching.
Quick and dirty critique on that sketch, though. You do need to work on your basics. Not only in anatomy, but general sketching. I'm sensing a bit of struggle between you and your tablet. maybe experiment with your brush settings until you find something that flows more naturally, like pencil on paper.
Here's a nice resource for anatomy practice. I recommend studying anatomy from life before studying anatomy from another artist's approximation
check out their 30 second drawing tool
Good luck out there, hope this was of some help