Is it possible for me to get a major in the degree im minoring in after i graduate ?

Math is an excellent undergraduate major for Actuaries.

Look at the Actuarial program that probably is your first choice. See what undergraduate courses they require. If you complete those courses, you can major in poetry for all anyone cares.

Here is a decent state program to consider - for the program and also as a benchmark

http://www.utdallas.edu/admissions/graduate/degree...

Where are you in your studies? If you're graduating in 3 weeks, then yes, it's probably a little late. However, if I wanted to be an actuary I would switch major and minor and go for stats. Alternatively, a double-major of math and stats gets you both degrees simultaneously and may add only a single term to your undergraduate time. You can always get a second degree either a Bachelor or a Master's in stats.

Going for a major after you graduate makes you a second bachelor's student (aka second degree students etc..) and not every university would consider this type of student. Other universities do, but may have restrictions. They might consider Stats to be similar to your first degree, math, so who knows if they will proceed with your second degree application.

You are going to have to search for good universities that will consider an application from students seeking a second bachelors. Or you can look into the graduate programs in actuarial science. Maybe you can look for entry level underwriter jobs or something related with your math degree.