Applied at McDonald's for Unknown

I recently had an interview for a position at McDonald's, which turned out to be quite an experience. I applied about two weeks ago, but my initial interview was canceled late at night. The next morning, I found out about the cancellation and received an email to reschedule, but all the available slots were already taken. After some back and forth, I finally had my interview today. When I arrived, a staff member handed me a form to fill out with my personal details and work experience. After submitting it, the manager came over to conduct the interview. To my surprise, she didn't ask any typical interview questions like "Why do you want to work here?" or "What are your strengths and weaknesses?" Instead, she only inquired about my availability and whether I could work more hours. I responded affirmatively, and she said she would check the schedule and get back to me. About an hour later, she called to ask if I could work three consecutive days and if I had a flexible schedule. I told her I needed to check my calendar and would let her know. When I called back to confirm my availability, she mentioned that she was considering other applicants and would inform me if I got the job. Honestly, I’m feeling pretty frustrated because I don’t think I’ll get the position. I realize now that I hesitated when she asked about my availability, which might have cost me the job. I'm 17 and just starting college, and I guess I didn't fully grasp how crucial it was to show immediate flexibility in a fast-food job. It’s a learning experience, but I’m definitely irritated by how it all went down.