Eventually, I think it comes down to presenting yourself in the best light possible. Not everyone who applies to HBS (or is admitted) has a stellar background. Having a strong GPA and GMAT is always good. As for your experiences are concerned, I think it's more about trying to understand which ones you want to talk about and what it will tell the adcom about you.

You definitely should apply. Cliched as it is, if you don't, the chance you getting in is zero.
(Take what I'm saying with a grain of salt, though. I'm an applicant myself)