It takes most people several months to feel like they really know what they are doing, no matter the job and no matter their intelligence/inherent ability to do it. The only thing that tends to shorten the initial learning curve is having done a similar job elsewhere. But even then, every organization does things differently, and no two jobs are exactly the same.
Based on what they said, I'd guess that it takes 2 months for the average employee in that position to be able to operate without assistance, i.e. answer standard questions without needing to consult others, know where supplies are stored, know what to do to close the gymnasium and fold equipment, be able to operate things like the coffee machine, etc. It would then take another 2 months for all of those tasks to become familiar rather than just possible, and to get some experience with handling unusual situations that don't come up very often.
If they normally hire college students, they're most likely hiring people with very little professional work experience. If you have more work experience doing similar types of jobs than the average college student hire, you might find you can adapt to the role more quickly. But it really all does come down to experience, and the more experience with this type of job a person has, the more likely they are to be able to secure a non-entry level job that probably pays better (and therefore be less interested in an entry-level one).