Why did my crush friend and sister follow me?

First his sister followed me I didn’t think much of it but she followed me for only a month then unfollowed so I unfollowed her back than 2 months later my crush followed me? I was confused I didn’t follow back bc I was kinda nervous but then he unfollowed me then recently he followed me again but one of his friends followed me too? Anyone know what’s going on?

Why did my crush friend and sister follow me?
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