Hi Londinium,
To start, the GMAT is a consistent, predictable Exam, so you CAN train to score at a higher level. Whatever 'issues' you might have with math, you will need to train to overcome them though. Thankfully, most of the 'math work' that you'll have to do on Test Day is limited to basic Arithmetic, Algebra and Geometry. You'll need to learn all of the necessary formulas and rules - and you'll have to learn patterns and Tactics - but again, all of this is defined and predictable.
Since it sounds like you're just beginning your studies, then it would be a good idea to take a FULL-LENGTH practice CAT Test; you can download 2 for free from
www.mba.com (and they come with some additional practice materials). If you want to do a little studying first, so that you can familiarize yourself with the basic content and question types, then that's okay - but you shouldn't wait too long to take that initial CAT. That score will give us a good sense of your natural strengths and weaknesses and will help provide a basis for comparison as you continue to study. A FULL CAT takes about 4 hours to complete, so make sure that you've set aside enough time to take it in one sitting. Once you have those scores, you should report back here and we can come up with a study plan.
I'd like to know a bit more about your timeline and goals:
1) What is your goal score?
2) When are you planning to take the GMAT?
3) When are you planning to apply to Business School?
4) When you refer to a 'severe diagnosed disability in math', are you talking about an actual medical diagnosis or that you've never really developed math 'skills'?
GMAT assassins aren't born, they're made,
Rich