Is it Weird For My Younger Brother to be Taller Than Me?

I am 19 years old literally about to be 20 in less than two weeks and my younger brother is only 13 years old yet he is about an inch taller than me. For that matter, our mother is taller than me as well. Despite being the oldest child and the most responsible one who fills the role as third parent, my 13 year old brother is taller than me and is still growing.

What happened? I literally think I may have some condition with how short I am. I am only 5'3" and I reached this height when I was about 15 and then just completely stopped growing. Even my doctor found it weird but never said anything further. Is this weird?
Is it Weird For My Younger Brother to be Taller Than Me?
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