I saw a hotel looking for a cashier, but I was embarrassed to go in and apply for it. I was afraid that people would dislike my youth and not want me, so I never did it.

There is nothing to be embarrassed about. Job requirements are two-way. He may not want you if you apply. Maybe you went, looked at the environment or something, and left immediately. Maybe he hired you, you worked for a while, you got bored, or you might leave.

Finally, you said that you are still young, so be careful not to fight child labor. Moreover, cashiers usually press ID cards and the like to prevent employees from making mistakes.