Nosmosis
Contributor
Take fundies. You get nitrox certification with it and learn some rescue (diver lift to surface). It will also make you more oriented towards team- diving, which is a similar objective to rescue, because rescue is usually emphasizing becoming more situationally aware, being a better buddy, etc. You will get all of this in Fundies.GUE, although I am biased.
Reason: first build solid foundation, then add other pieces.
In my view, the skills you build in a fundamental course are the most basic ones, so I always suggest to do that course as soon as possible.
Just my view
After that you can take the GUE Rescue Primer.