my sister got stung by a jellyfish

Me and my sister Lily were playing in the deep end of the ocean, and my dad said “Don’t go to deep” I'm like dad were fine we will not go to deep". So we went out deep and I and my sister just started playing in the cold salty water! I knew not to go to deep because maybe a jellyfish or a shark will be out there. So my sister said "ow I just got stung by a jellyfish I rushed to shore to tell my dad “Lily just got stung by a jellyfish "! He said “why did you leave her out there ",I said sorry it was an emergency'! So my dad went to get lily to go to the lifeguard to see if they had anything to get the sting away. So the lifeguard said “put some olive oil on your sting". So we went to back to our beach spot and my sister just let her knee heal. Meanwhile I felt bad for my sister. Because I just left her out in the ocean half way to shore. This actually this happened to my sister a lot so she was kind of used to it. Luckily I never got stung by a jellyfish. Because I always ran to shore! Now I know don't go to deep because there are jellyfish out there!