More than you're ready for
It’s almost never a good idea to take on more than you’re ready for. But you might find that it’s really hard to know exactly what you are and aren’t ready for.
You probably can’t trust your own intuition on that front. So either go for it (if the stakes are low), get a second opinion from someone you trust, or find a way to remove risks or increase your certainty. Can you start out by doing a smaller version?