@frazi78
The programs that @moonchild is talking are SMPs. Most SMPs require a MCAT score for admission.
MCAT scores are good for 2-3 years. (AMCAS says 3 year from the date of testing, but a few med schools will only accept MCAT scores that 2 years or less.) You should take the MCAT after you’ve finished your pre-reqs and after you’ve had time to prepare for it. You should be consistently hitting your target score range on full length practice exams right before you take it.
Retaking the MCAT is just something you may need to do if you want to attend med school. It’s hoop that you need to jump through. The MCAT won’t be last major standardized exam you’ll have to take if you want to be physician–and it will be the easiest by far.