Not too bad for a full body selfie. Yes, the shadow was the first thing I noticed too, but I picked up on a couple of other things not mentioned yet or I completely missed. So if you don't mind, a few thoughts.
Back to the shadow first. Did you try any using the built-in flash for Fill? Had you, the defined shadow line may have blended better, probably not eliminated, but lessened the obvious issue. With time behind the viewfinder you will start "seeing the light" in a different way and how to best utilize or modify it.
What I'm surprised at is the lack of comments about the tree growing out of your head or the two limbs impaling your back (dirty rotten cowards

) Again, with more time you will become more cognizant of the immediate and distant backgrounds.
I'm in total agreement that an aperture of f/8 to f/11 would be worth having a few attempts at for sure. I'm not a fan of overly bright backgrounds in most cases, of course there are exceptions. Add to that some flash and well….. it would’ve given you a slightly different exposure.
A few things to consider on your next attempt......... because there will be another attempt, right? With or without a bikini.
1) Do not sit flat on your bottom. By placing your weight on one hip, you will naturally create a more dynamic pose if you do nothing else.
2) I would avoid rolling your shoulders forward. This sends out a negative body language. Sit straight, but bend at the waist, no slouching allowed. A strong, dynamic position would be to have the shoulders somewhere between 20° to 45° from lens axis, with a slight lean away from the camera.
3) I suggest having the far knee at a 45° and extending the near leg and crossing ankles. Due to the lighting you have, this position would give more detail rather than the rather large dark area underneath your legs.
4) Think about the lines you can create with all your body parts.... arms, legs, head, hands, etc. Accentuate those lines.
Thanks for sharing.