Here's the line art. I refined the trident more as well.

This is gonna look amazing! Thank you!

I was thinking of putting the light source down at the bottom so the shadows go up. Here's what it would look like. If you would rather have a more typical top down shading that's okay too.

I agree with your idea for the lighting! It looks better!

Btw is there a way to incorporate her sign Piries into this?

Hi! If this is still open, would you be willing to draw a half body of Bea?
Reference:

For clothing + pose, feel free to do whatever, she does tend to wear a lot of oversized sweatshirts with bright colors if that helps :)

Yes it is open. I can send you a sketch after I'm finished with my other commission.

Okay! There's no rush, take your time :)

Flat color. Plus colorful splat version. You can pick which one you like. (Or I can do both it wouldn't be much more difficult.)

I love the bottom one, and you can do both if you want to! And is there a way to add this symbol into her design?

http://hs.hiveswap.com/ezodiac/truesign.php?TS=Piries

It originally says it was on her crown. Although due to the angle of her head I'd be hard to see it on top of her head. We could add the crown into her open hand if you want to stay true to the original description. Some other options could include on her chest, stomach, or trident.