Do you need to build something (& exit) before you can be an angel investor?

I would love to one day be an angel investor. Being in a position of expertise and advice and mentorship/encouragement to young (or old!) inspired entrepreneurs wanting to create amazing products for their niche would be so bloody cool to me. But before I can do that, I feel you need a certain level of net worth to allow for enough plays and risk tolerance. How do you get that base level? Do you need to build something yourself first and potentially sell it?