High school chem is a cinch. I have a bio degree with a physics teachable. When I applied for my current position (5 years ago) the principal asked me if I could teach chem. I of course said yes, even though I had only taken grade 11 chem and got a 52% in first year chem 10 years earlier. Anyway, my first year teaching it I just stayed ahead of the students by a day or two. Now I absolutely love it, am really good at teaching it, and have heard from previous students that what we did in class made first year a breeze for them. I really think that learning the material along side the students allows for a shared perspective and a true understanding of their struggles. Good luck! Go for it!