I'm not in a startup, but you should comfortable answering/acknowledging something along the lines of we needed it working quickly, and this did the job for x amount of time based on the time available at the required throughput.

We have the time now for refactoring ... or we'll add a ticket to the backlog, etc.

Second, everyone looks at some code, wonders what idiot did this ... and at some point discovers it was themselves x months/years ago. If you're the primary coder, you'll be getting this a lot. Accept that you've learned and improved since then.

Hope this helps.