Hi i am a 13 year old girl how can lift a lots of weight is it normal?

You're strong is all, and that's a good thing, to be fit. When I was a teenager I used to look after sheep and goats and I could lift big bags of feed and bales of hay and buckets full of water, and haul big rams around. My dad always commented that my arms were big. I was strong and felt great. (Now I'm totally domesticated. My arms are still big but the muscles, well... My 3rd son is called Tariq). Stay strong and healthy. Don't beat the boys up!