I can't help with the relgious side as I am Church of England.
But my mother is always hasstling me to cut my hair. In Decem,ber 2009 I gave in to the constant pressure - I was somewhere between TB and Classic and I cut off to BSL when wet. I was busy with a sick child and only 6 months later it hit me. I have to say I regret cutting that much off. A trim to waist or hip would have been enough and I would have reaslised I wanted longhair without taking so much off.
Back at hip now my mother is back on the bandwagon. What I do is wear my hair up in a bun everytime I see her - she has now idea how long it is now and with it tidyly away she often forgets I have long hair!