Not bad, I would certainly think about it. In addition to padding the SWR, it will also likely serve as a nice reinforcer of why you wanted to be FIRE in the first place.
Just make sure you get the math right on a couple of things:
1. You will have to pay both sides of the payroll taxes (SSI, Medi) - so that will be 16%.
2. Factor in state/federal taxes that you will be responsible for - each dollar of additional income is at the marginal brackets above your current ones.
3. Employment costs (commute, clothes, meals, etc) that typically come with jobs.
4. Insurance - if you are using ACA then this would/could have an impact.
Anyway, $100k could quickly become $50k if you don't plan accordingly....and $50k may change your view or not as you may want to just do something. There are some ways around this stuff but you may need time to explore.
Its all about thoughtful decision making.