You found a gorgeous Golden Orb-Weaver spider! She's an adult female (the males are very tiny) and she's completely harmless. IF she bites, which is rare, it'll be a little sore, like getting an injection, but you'll be fine as long as the wound stays clean. They look scary, and because they're so big, a lot of people think that they're dangerous when it's exactly the opposite. Their golden webs do tend to get very large, and some have even been recorded as eating birds that get stuck in them, which is amazing for such a small thing to do.