I was under the impression that the vast majority of startups fail. I don't think being a failed entrepreneur is a bad thing, if anything it's hard-won experience that should be valuable going forward. People expect startups to fail- actually succeeding is huge, but not getting there isn't a bad thing in itself. I can't imagine you would be judged for being associated with a startup that didn't make it, unless there were was something fundamentally unusual and terrible that happened that was scandalous or criminal or whatever.