Recommendations for second CC?

Hello! I am currently a college senior, 21 years of age, and wondering if now is the time to get a second CC. I’ve had the Discover Student CC since I turned 18 and my credit score fluctuates but has stayed around 750 for about 8 months now.

I recently downloaded Credit Karma where they advised me that I have a good chance of getting approved for an AMEX Gold CC. Is this a good CC? I have not been using my Discover CC as much as I should be, which makes me wonder if getting a second one is even worth it.

Anything helps!