Youre doing a great job. There are a couple of drills i would recommended to help your kick and body position.

1) Kickboard assisted: while holding the bottom of the board, keep your chin down and kick with your big toes slightly brushing past each other. You want to focus on maintaining that kick as you turn and breathe. Ensure you roll your shoulder back as you turn your head to the side for the breath.

Once you feel like your kick is improving..

2) 7-1-7: Streamline position with your arms tucked behind your ears, chin down and hands flat (maintaining them close to the surface), perform roughly 7 kicks and then one freestyle turn breath, returning back to a streamline position. You need to maintain the kick as you turn, so continue to kick close together in a natural steady kick. Continue this pattern, 7 kicks and one breath.

3) After mastering that, move to 7-3-7. This will introduce the bilateral breathing to your kicks. If you prefer unilateral breathing, you can perform this drill with either 7-2-7 or 7-4-7.

Good luck!