Do you have any notes from school? Either way, the interview process could be a good strategy for pinpointing any gaps in knowledge to gauge how much work you need to do vs. going for bartending. Once you are hired, I think it would be more practical to learn from your co-workers (even ones outside of your discipline) and utilize any educational assistance programs over spending so much on a degree by yourself. 30 years old is still considered somewhat early in your career, especially when one considers covid's effects on many career paths.