I want to start diving into BDD. I have never used TDD before and am not sure if I should start by learning RSpec and then jump to Cucumber or just go straight to using Cucumber
Kenton did a great job with this answer. Here is how the authors of RSpec and Cucumber see it:
We use Cucumber to describe the behavior of applications and use RSpec to describe the behavior of objects.
Although we use Cucumber to focus on high-level behavior and use RSpec to focus on more granular behavior, each can be used for either purpose.