Five minutes after winning the presidential election of 1904, Teddy Roosevelt vowed not to seek re-election in 1908. Six minutes after, he regretted what he had just said. He tried to return in 1912, but failed and regretted his hasty decision the rest of his life.
Why do I mention this? Because whenever I feel like I’m in a difficult situation (not all that much different from yours), I promise myself not to pull a Teddy Roosevelt and do something hasty that I’ll regret forever. Neither should you.
For what it’s worth, time is not slipping away. In spite of what you may think, 30 is not old.
My suggestion: keep your job and stay on your path, but find a way to do it and your startup at the same time. You have to get creative. Put in a few hours on your startup before work, not after. Get rid of you TV set. Block out huge blocks of time on weekends. Use your PTO for your startup. Work from home a few days a week and squeeze in extra startup work with the time/energy you save. You get the idea.
You’re already creative enough to build a startup. Now use that creativity to free up more time and energy to work on it. Forget about the competition and time slipping away; just do the best you can. And don’t pull a Teddy Roosevelt.