Do I Have a Short Frenulum?

Im 18 and I had never pulled back my foreskin until the other day. I did it while I was flaccid. It was hard at first but now its easy to pull back. There is a large ring of skin at the base of the head of my when I do this. It is much harder to do this when I'm erect and Ive only done it once now. And there is still a ring of skin. I know its supposed to go down farther. I may have a short frenulum. Now I have heard of stretching, is that just for the foreskin or can you stretch the frenulum. I definitely dont want to get cirsized. So if I do infact have a short frenulum is there a way to stretch it, or will I have to get surgery. If I have to get surgery can anyone think of a way to get a doctors appointment without my mom figuring out whats wrong. She needs to schedule it but I want to be discreet. If I really do have a short frenulum Ill tell her but I dont want to jump to conclusions. Thanks