Hi Innocent, thanks for your request for help but I'm really sorry, I can't help you much
I'm not a professional and nor do I have the training to look at a curve from the outside and try to work out what degree it might be - especially where kyphosis is concerned, as I don't have as much experience with that as with scoliosis. If you have any x-rays there are a few of us here who can try to measure your Cobb Angle from those, but again we are all amateurs and cannot guarantee how accurate we'd be.
Hopefully someone with Kyphosis here will be able to help estimate the degree of your curvature by comparing their own case to yours. All I can say is that compared to others that I have seen here, your curve looks a lot milder than many. Can you straighten the curve out simply by making yourself sit up straight? If so, it could well be a postural curve and physio might help you a lot. In any case, most curves do have some postural element so building up strength in your back can be very helpful with the way things look cosmetically (just be careful not to overdo things, as spinal curvatures can make it easier to injure discs etc).
Really sorry I can't help more