Cleaning my Macbook Air I just used some Rubbing Alcohol (I didn't use too much and I put the stuff on a paper towel first) to wipe and clean the keyboard and backside of said keyboard of my Macbook Air. Now I'm obessively terrified at the thought that I may have just made a costly mistake. I want to say that nothing appears to be happening yet, but I don't want to jinx it. Should I not have done it????!!!!!
It’s difficult to answer your question as the answer is, to some extent, opinion-based.
In their support document, Apple used to explicitly discourage consumers: (source)

Don’t use window cleaners, household cleaners, aerosol sprays, solvents, alcohol, ammonia, or abrasives

However, it appears that Apple has since changed the wording, eliminating the »alcohol« part:

Don't use aerosol sprays, solvents, abrasives, or cleaners containing hydrogen peroxide that might damage the finish.

In a related support document, Apple suggests to use disinfectant wipes as long as they don’t contain bleach:
(Note: I’m not allowed to post more than two links as I’m a new user. However, just google for HT201294 and the document will turn up.)

Use a disinfectant wipe to wipe the area first, then use a damp, soft, lint-free cloth, and finally dry the area with another soft, lint-free cloth.
Do not use disinfectant wipes containing bleach or disinfectant sprays in general.

This suggests that Apple has stopped discouraging customers from using rubbing alcohol, or isopropyl alcohol. Note that rubbing alcohol seems to be an active ingredient in the disinfectant wipes recommended by Apple.
Apple suggests a few brands of disinfectant wipes (Lysol wipes or Clorox Kitchen Disinfecting wipes). Ultimately, it is up to you to choose a product that works best for you.