MCAT 2015 or Now??

<p>I'm going into my junior year of undergrad and I was wondering if I should try to study hard and take the MCAT this summer, or wait until the 2015 comes out.
My older brother, who is currently studying to take the MCAT this summer recommends that I also try to take it this summer to avoid Biochemistry and the other changes in the test.
I have taken Chemistry, Orgo, and Bio but I haven't taken Physics since high school yet but my brother insists that I could learn it. Is it worth it for me to start studying now to avoid taking the new test in 2015?</p>