Assessment context and image originals from this thread:
https://www.reddit.com/r/PostureAssesments/comments/14w0ito/it_is_bad_asf/
Before I start, I have to comment on the side view - it looks to me as if you would be touching the door jamb with your bum. Even a light touch will affect your equilibrium / balance - effectively that point of touch is helping you to balance. That of course has an impact on the overall coordination of the entire mechanism. In other words, the touch will affect how you are standing. Saying that, your postural habits are well visible anyways, so I can assess. Just wanted to let you know that without the touch, you would have slightly different shape, my guess would be that the iliacs (the blue point at your waist) would shift even further forward.
Also, the green plumb lines on the the front and back view have been adjusted to the camera distortion.
Ok, lets dig in.
Feet not in correct position. Toes apart, heels together. The blue lines at your feet (the out steps) would need to be parallel to each other (and heels closer together).
Ankles and knees released (flexed).
Iliacs (anterior superior iliac spine) too much forward and down. Sacrum (not marked) lifted too high up. As these two points are on the same structure (pelvis). Imagine, that as seen on the image, the pelvis is rotating counterclockwise. Pelvis is your lower torso.
If we shift to your upper torso (ribcage) you will see the complete opposite rotation (clockwise). The yellow line, is your sternum. that indicates the amount of lean of your upper torso back at the top. Your ribcage is literally inbetween the yellow line and the straight top of the red curve marked at your back.
These two opposing movements (rotations) of your pelvis vs. ribcage is what is "bending" your spine - red curve. What this means is that you are shortening and narrowing your torso, compressing your internals, limiting breathing and constricting blood circulation (apart from other things).
The blue markers (ankles, knees, iliacs, bottom and top sternum) should all be on the green plumb line in order to get proper functioning of your mechanism.
You are pulling your shoulderblades together at the back (retraction), shoulders are lifted up and back. The entire mechanism of your arm is shifted back.
The pink line at your cervical spine shows the shortening of your neck. Head is retracted as well, you can see your chin (grey line) way back past the bottom sternum. If you imagine all the blue spots on the green line, top and bottom sternum would be on the same vertical. If that would be the case, your head would go forward, chin being good 2 inches past the sternum (that is now vertical). You would completely loose the double chin.
Also, I didn't mention your abdomen. We call it "protruding" abdomen and its a result of the shape of the spine. You could copy paste the red curve and place it at your front and it would match. (I often do it, not sure why I didn't copy pasted it in this time). Seems to me like you have little bit extra body fat, but that "beer belly" of yours is actually not beer belly at all - your abdominal muscles are completely out of action, simply sagging out. Most guys with your body shape I worked with cut the belly by at least half (often more) on first lesson (when having in person lesson, as I can be more brutal with them), but every student will get this by lesson 3.
Let's look at the left right imbalances. I don't really want to say for sure you are placing one foot in front of the other. Possibly, and if so, it wouldn't be much. But the pattern on the floor going diagonally really messes with my eyes. So will leave this one out.
You can however clearly see the tilt of your pelvis sideways (orange lines). This tilt isn't possible without a rotation in your pelvis. If you would be to stand in front of a wall with your feet squared to it (both toes the same distance from the wall), and measure the distance of your iliacs from the wall (either side), you will find that one is closer to the wall than the other. I'm guessing the left iliac will be closer to the wall than the right one. (If you test it, make sure your feet are same distance from the wall - use a physical object to delimit this distance).
There also must be a rotation in the upper torso in order to balance you out. Looks to me like the right side is more retracted back than the left. (you can see the right scapula (shoulderblade) sticking out a little more.
And to finish, you are clearly loading your entire right side more than the other. There is more mass shifted to the right.
By your 12th year, all these habits of movement would have been well and truly established and they would have been getting worse with time. Resulting in what we see on the images.
Taking a picture like you did, having a good look at it facing the reality and even getting assessment like this is massive. I really commend you for doing that. Becoming aware of what is going on is the first step in order to do something about it. It takes guts and it's not easy. Well done mate.
Good news is that since all your bad postural habits are learned (not consciously, but learned nevertheless) you can also learn to replace them with different way of coordinating your system. It's certainly 100% fixable, although, it doesn't just happen on its own. It takes learning, which is effort.
To learn to coordinate your mechanism consciously is a task with complexity comparable to learning a foreign language. It is also a lot of physical work. A lot of physical work. It's not uncommon for students to feel tired within 10 minutes of experimenting with conscious control just like they would after an hour long workout.
There is plenty of teachers worldwide like me who can help you to learn to change your posture. What you are after is an initial Alexander Technique teacher. Your best bet is Jeando Masoero, who effectively developed the modern way of teaching the AlexTech. But any other IAT teacher will do too.
If you want to try it out, I give 3 free lessons - enough to find out if it is for you or not. As i said, it's a lot of cognitive and physical work - not everyone is willing to commit to it.
If you have any questions, or didn't understand any of what I have written above, please do ask. I'll be more than happy to elaborate more.