I am talking about the length of it. We measure saddle length from the nail head on the side of the pommel toward the top to the center back edge of the cantle.
With me, a 5’3 1/2" female with long thighs, I need a 17" saddle, a 16.5" saddle runs my pubic bone into the pommel, a 17.5" saddle is a little bit too big for me, and an 18" saddle puts me into a chair seat position (like I am sitting back in a chair) and it is harder for me to go with the forward motion of the horse. With some saddles, even if the seat fits, I need a more forward flap, otherwise my knees end up on top of the knee rolls. This is all with jumping saddles.
I have more problems with the AP (All purpose) saddles and the GP (general purpose) saddles because often there is not enough room for the length of my thigh. I do own a dressage saddle (17.5") and I had to rip out the knee rolls because my knees went over them and floated in the air, without the knee rolls my knee still goes beyond the front edge of the the flap but I can handle it a lot better since the length of my thigh can stay against the saddle flap. I also took off the knee rolls of my GP saddles (velcroed in) for the same reason, the front ligaments of my hips HURT.
As you can tell from the above fitting a saddle to a rider can often be challenging, then you have the problems of fitting the saddle to the horse’s back.
And another thing, just because at 5’3.5" I NEED a 17" jumping saddle does not mean that a 6’ tall man cannot fit in THAT saddle, though a 17.5" or 18" saddle may be more comfortable for him.
As for specific saddles, ask if they have an older Crosby jumping saddle that is 17" or bigger (you probably need bigger), the pommel will interfere with you less. Pancake saddles can help a lot with your specific problems.
My story–my first pregnancy I rode in my 18" extra forward flaps rather deep seated Stubben Siegfried and it did my pubic bone in big time. My next pregnancy I used my 17" Crosby saddle with regular length flaps and I had no problems at all because the Crosby is a flatter saddle than the Stubben Siegfried and I had zero problems with running into the pommel even though the saddle’s seat was 1" shorter.
Just remember when you talk to your older riding teacher–she has probably heard it all, she definitely knows what men look like down there, and she will probably be sympathetic. I’m 70 years old and I would have zero problems talking with a younger male about this in person. I seriously doubt she would feel embarrassed at all.
Good luck. We are all on your side about this. We KNOW how miserable a too small saddle can be.