Should my bachelor's degree match the graduate program that I am trying to get into?
Rather than providing you with my opinion (I think you're aspirations are realistic), I think you should contact the admissions and academic advisers of your chosen post-graduate institution and ask them.

Ask them about your proposed course of graduate studies.

Ask them about how much course work you may need in order to "catch up" to other students planning to enter that major field of study.

I believe most institutions will allow you to start your post-graduate studies while you're still taking any undergraduate classes you may need.  The only way to know for sure is talk to someone at the University.