Then I would say... maybe. But +13 athletics would not be what I would use to judge this. Having Mystic Speed is a good first step though.
You’re like the wind itself. Hell, you may be the wind itself.
After that, the question is who are you?
Are you the wind itself? Then you can certainly hit Mach speeds. Are you the Flash? Superman? Sonic the Hedgehog? Of course you can hit Mach speeds. If your character concept is more focused on short bursts of speed, like a super kung-fu monk (or a better example I can't think of right now), you'll probably want to have speed powers as well, but even with Mystic speed, you might not hit Mach speeds, because that's not who you are.