Should I be mad at my sister?! We were at the local pool?

I'm 13 and I don't really consider her my sister because she is only my half sister because we have the mom. But she's 19 and she took all the kids to the pool so it was her and 9kids. And when we got there we changed into bathing suits and I jumped off the high dive. After that I was bending over waiting for my little sister to jump off the low dive. And my older sister put her hand right below my butt and pushed me in! As soon as I got out the pool I was mad cuz I realized I was bleeding above my eye then she had to take me to the ER and I had to get stitches! She apologized then we went back to the pool. I got in the water again but not the deep water and I couldn't go under water thanks to her!