Cofounder is significantly younger than me. Should this be a concern?
We are in different stages of life. She is more naively optimistic and wants to move rashly, I am more experienced and want to move more thoughtfully. Different risk appetites. She's bought into the VC-backed glamor. I am disillusioned. But we share the same passion, our skills complement, and we have a working history.
Has anyone successfully managed a situation like this?
You'll balance each other out, but ultimately someone needs to be the singular decision-maker. And the other needs to be willing to offer their perspective, but then respect, accept, support, and follow the decision that is made.
If you guys can decide who plays which role, you could be great together. But if neither of you is willing to go down the other's chosen road, you'll ultimately clash and be frustrated.
Is she at least 24-ish, to be (neurology-wise) a full adult?
How well do the two of you handle the conflicts that your differences create?
What is your feeling for the worldview and motivations that she'll have to fall back on, when (all too likely) the cold water of reality drowns her current VC-backed glamor ideas?
As others said, each one of you gets a different perspective and it's definitely good. But are your goals aligned? Usually people in different stages of life have different goals. Just check both are compatible with the startup and you should be fine.
It's big advantage. Different view points, different approaches. If you have 'good vibes' together it can bring amazing results. You can learn a lot and she can learn a lot!
Mutual respect is the key.
You balance each other out. Assuming you can communicate your thoughts respectfully and argue without devolving into mayhem, this is actually a really powerful combo.
You are in an early stage start-up? You need a risk appetite to succeed, surely? So, if she offsets your conservatism, that's good, surely. And vice-versa.
This sounds like an awesome, enviable fit if anything.
Won't matter until you have a product to sell.
sounds like a perfect fit