Degrees of a Sign

With astrology it seems there is always more to learn. I was surprised to learn that the degrees of a sign meant how far you were in understanding that sign and the house that sign rules.
They divide the 30 degrees of a sign into 3 parts 1-10 degrees represent astrological kindergarten, where you are learning
10-20 degrees represent the working degrees of a sign
20-30 degrees represent spirituality.
The planets in the middle are the ones you use in everyday life. I am a Sun in Sagittarius at 26 degrees and my Sun is spiritual and yet only a backdrop, a background. I have two planets at zero degrees and I know nothing about career or friendships, the houses that these signs rule. Yes I mean I haven't the foggiest idea about my 10th or 11th house.
Ourselves are mysterious, how great it is to finally have an explanation! The world makes sense again through astrology.
The only planet I have in the middle of a sign is Mercury. Mercury is the planet of communications. Every day I think about communicating and how to communicate, this is my focus. Even when very young I wrote things and was amazed at how the act of writing made me feel better and I didn't know why then and I don't know why now. It just works.
I wrote that my Sagittarius is only a background, but that could be due to it's conjunction with Saturn. Saturn puts the brakes on any planet it is next to. I do have Venus in the last 10, and beauty for me does move me spiritually and no, it is not in the background. So I think the loss of my Sagittarian nature is entirely due to Saturn's influence.
My planets in the first 10 degrees seem to express themselves in a wild manner. They seem to be a part of me that is instinctive and reflexive. Being not fully integrated into myself, they seem to be the thoughts that come to me and make me ask, "Where did that come from?" These energies are not something you make happen, they are something that happens to you. Pluto rules jealously and I can be suddenly and violently jealous. Jupiter rules optimism and I am optimistic even if I have just lost my car, my job and my boyfriend all at once. Neptune is the planet of illusions and I do tend to be pulled into dreams or into thinking that is just not real, not what really happened or could happen. These 3 planets in the first 10 degrees make me have to reason them out, 'cause they are illogical. These energies sometimes wipe me out and I don't even make sense. I am pulling nonsenical things out of the air.
So it is I guess that I work with creative projects, 'cause I couldn't be a jet pilot or a doctor for sure. I believe there is the job we are supposed to be doing, what God wants us to do. This is what we have these talents for.
We have a purpose in this lifetime, and part of it is figuring out what our purpose is.