Cutting hair to make it all of equal length is permissible so long as one does not resemble the kuffaar

Cutting hair to make it all of equal length, reaching
the shoulders or ears is OK, so long as that does not involve resembling
the kuffaar. Resembling the kuffaar is haraam even if it is in regard
to something that in principle is permitted. 

With regard to cutting some of the hair and leaving some
of it, that is not permitted. This is the hairstyle which was forbidden
by the Prophet

(peace and blessings of Allaah be upon him), as is narrated in Saheeh
al-Bukhaari and elsewhere. 

This ruling applies to both men and women. It is OK to
cut the hair and make it of equal length so long as that does not involve
resembling the kuffaar, or making men resemble women and vice versa.
Women should not cut their hair short in a manner that resembles men’s
hairstyles.