I have $21.50 and I'm gainfully employed as of last Thursday. What should I do with it?

Honestly, I have no clue how to budget my money. I'm 15 and just got my first paycheck from my job as a lifeguard. If it helps, I get $22.50 every Thursday and I earned this money by working 2 hours on Friday, 4 hours on Monday, and 4 hours on Tuesday of last week. I have $21.50 remaining after spending $0.50 on a cookie.<br><br>What should I do with this money? Should I put it in a savings account, keep it in cash, or spend it on something like a Nintendo Switch? I'm not sure how to properly budget my new income.