ok its been 10 months and ren has grown but shirayuki's hair hasn't?
then try to explan this: https://lh5.googleusercontent.com/-xCUCqn1Uyrs/U_gcUdsjwkI/AAAAAAABi3g/vCt9cBxcZfs/w500-h1231/tumblr_naqcdzM4Zl1sqqx06o1_1280.jpg
It has slightly. Since she cut her hair, it's been getting slightly longer. Also, she might be cutting it too.
i thought it would be growing faster since its almost been a year.
I would agree.
ok its been 10 months and ren has grown but shirayuki's hair hasn't?