I was also one of those people. I will point out that we (until we get some time working really close) are naturally easier to pressure backwards, because we instinctively tend to want that space back. It'd be worth getting into some close and tight grappling even for just a few months to reduce that natural tendency.I agree with what everyone has said. I'm sure you get over it quickly. I've always been one of those people that likes a good deal of personal space, even when talking to people. I do want to become somewhat proficient at basic ground defense/grappling/kicking so at some point I will engage in it. Please don't mistake what I'm saying as a negative for grappling arts.