Should I change to law to help become a JAG?

Your not alone, I have similar fears I wanted to become a Defence engineer but my maths was not good enough,I am currently doing A-levels in History,Politics,Sociology and English and repeating my Maths GCSE, my point is not to worry, no matter what way you go you have an education behind you and that the main thing, its never too late to change, if you like law then do it !, don't hold back your 23 not 80 you have your whole life ahead of you, don't think that your gonna waste it, the best way to resolve your dilemma is to do research into being in the JAG and routes that are available, you might be very surprised, I was, my choices at A-level opened up a range of military related careers I never even thought of, now my aim is to do War studies and History,with a postgrad course in science and security, also consider postgrad options.