From Longman Dictionary of Contemporary Englishmake up your mind/make your mind upmake up your mind/make your mind upa)DECIDEto decide which of two or more choices you want, especially after thinking for a long timeI wish he’d hurry up and make his mind up.make up your mind/make your mind up aboutHe couldn’t make up his mind about what to do with the money.make up your mind whetherKaren couldn’t make up her mind whether to apply for membership or not.b)DECIDEto become very determined to do something, so that you will not change your decisionNo more argument. My mind is made up.make up your mind to do somethingHe had clearly made up his mind to end the affair.make up your mind thatI made up my mind there and then that I would never get married.c)to decide what your opinion is about someone or somethingmake up your mind/make your mind up aboutI could never really make my mind up about him.You’re old enough to make your own mind up about smoking. →mind
Examples from the Corpus
make ... own mind up• They would be able to read the newspapers and make their own minds up about the corruption and deception going on.• I made my own mind up.• You will just have to make your own mind up on my views.