Staying at startup or leave?

About three months ago, I left a big tech company—just seven months in—to join a seed-stage startup. It had always been a goal of mine to experience life at an early-stage company, and I figured the timing was right: I was early in my career, eager to learn, and ready to take a risk.

Since joining, the startup has made some progress. We recently raised our Series A, which is exciting and definitely a milestone. But now that I’ve had time to settle in, I’m starting to question whether this is still the right place for me to grow.

The toughest part so far has been the hours. I'm often putting in 12-hour days, six days a week. I knew startup life would be demanding, but the constant grind has been more taxing than I expected. While we did raise a Series A, I’d say I’m about 50-50 on how confident I feel about the startup’s long-term success. Some things are promising, but other aspects still feel uncertain.

From a learning standpoint, it’s been a mixed bag. I’ve picked up a lot just from being thrown into the fire, building fast, and working directly with founders and early team members. But we don’t really do code reviews. There’s little mentorship or structured feedback, and I worry that I might be missing out on developing stronger fundamentals—especially important for me as a junior engineer.

I’d love to hear thoughts from folks who’ve been in similar situations: Is it worth sticking it out longer at a startup like this, or should I consider moving on?