Master Degree in SpEd

I'm thinking of enrolling in a master's degree program. It's my second year teaching in elementary even though my specialization is secondary majoring in Social Studies. I'd like to pursue a Master's Degree in Special Education.

Question for teachers, is it a big adjustment if my major isn't exactly aligned with the master's degree I choose? Any tips for those who are already in a master's program, especially in SpEd?