Where do I start with math and biology?

For improving math should i work through the grades starting at 1? And with biology what do I start with? Should I go Into the biology library or do middle school biology? I left school with nothing - no sciences etc. I'd love to learn basic biology, how should I start? I work with animals as a nurse assistant and I'd love to become a nurse one day. I'd love to do a biology course out of interest and to help with a future career (the concept blows my mind and sounds so interesting). My problem is I left school with literally nothing. I've blocked out the entire experience and didn't do or pass any science classes. How can I get started? I've read I need to understand basic chemistry to understand biology? And to understand chemistry do I need to learn complex math? I also struggle with math and would like to improve this skill. I'm at a loss and feel very overwhelmed with where to start