Why did he ignore me?

Ok I'm asking this on behalf of my little sister who is in 8th grade. I already told her what I think:

I brought cookies for everyone after band practice. Everybody came and got one but not my crush. He will talk to my cousin but not me. Sometimes I wonder if he is looking at me and not something or someone else. Im so confused on how to tell if a guy likes me.

Why did he ignore me?
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