how high is a "high" cervix?

I'm learning about cervical positions and where it should be at different points in my cycle. How low is low, and how high is high?

I'm supposed to start my period today. I reached my whole middle finger up as far as I could reach and it seemed like it went very deep. I thought I felt my cervix, but it didn't feel much different than the walls of my vagina. I could tell it was a lump but couldn't feel if it was open or closed and didn't feel particularly hard. I have looked at pictures and I know what it's supposed to look like but actually knowing if it's high or low is a struggle.