Is it normal that i easily forget things?

Recently, I easily forget everything. Just like, when I've just done something, just some minutes later I will forget all. Sometime I know who I am, I know my name, but I don't even know why I was here. Sometimes, I go to my friend's house but then I completely forgot why I went to here.
Note that I'm not old yet. I'm just 13 years old. I'm afraid that I am not normal.
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(Sorry for my bad English)