I believe it is 3.2 Emotions that I found my problem. I was taught in school that men saw "nervioso" and women say "nerviosa" but in the lesson Amy says "when talking about a woman use nerviosa and when talking about a man use nervioso. As you can imagine, this is very frustrating to me because it conflicts with what I've believed to be true for so long. Ayudame por favor...

Nervioso/a is an adjective and it is adapted to match the gender of the noun it describes. So if talking about yourself you would use the "a" if you are female and the "o" if you are male. Similarly you would use the appropriate form if describing anything else depending on whether it is a masculine or feminine subject/word/ noun. O= masculine. O = feminine. I hope this helps.

Oops! Correction: A = feminine.

I see! Your explanation makes sense and thanks for writing.