[dotBen]

I think you give yourself a hard time - part of the reason you're older is because you're doing a post-graduate program and not everyone does that immediately after their under-grad.

So I actually have an open req for such an intern at WP Engine (http://jobvite.com/m?3aIqcgwf) and I think a post-grad intern with your experience would be ideal. So there's no way age would be a factor, (and legally, it can't/shouldn't anyway)

On your side, I agree with other commenters that you want a clear definition of work to ensure you get the experience you actually want. You probably want to lean towards more established startups who can create a program of work that really needs your skills. We're almost 4 years old and I don't think we'd have been placed to capitalize on your skills and in return offer a meaningful experience 12-18 months ago just because the type of work your doing is probably not relevant during the 'scrappy years' of a startup.

Good luck!