Allison's Cruise Ch. 1

Allison is fifteen year old girl and is going on a Cruise with her family. Allison's 18 Year old sister named Catherine, her 8 year old sister Vanessa, and her mom Audrey. Her dad is not in the picture.
It was the first night of the Cruise. Allison was sleeping peacefully in a queen sized bed with Vanessa on the other side. The day had been a long and tiring journey coming from the airport and getting through security onto the ship. While the dinner had been super nice, she hadn't really enjoyed it she was so tired. Noticing that she was tired her mother told her that she should go to bed. It felt so good to hit that bed. She almost fell asleep instantly if not for Vanessa turning on the lights for her to get ready for bed. Allison lay there as she heard the toilet flush and then when her sister walked out to grab a pull-up from her suitcase. Soon enough Vanessa slipped into bed in nothing but a shirt and pull-up and they both drifted off to sleep. Daylight poured in through the window as Allison woke. What an amazing sleep. It had been so good that it must have been the reason she felt different this morning then she usually did. Getting out of bed, she noticed a cold sensation at her crotch. She immediately opened her eyes wide open and looked down to her horror to see a large wet stain on her pants. In a panic now, she ripped off her sheets to see that they were absolutely soaked. She moaned, Why did this happen to me. Suddenly, Vanessa woke up to her sister's cry. After taking a quick assessment of the situation, she hurried over to her older sister hugging her and told her that it was all right that it happened to her too. The thing was Allison didn't want to be like Vanessa. Allison was supposed to be the older one who would be someone for her sister to look up to not a girl who peed her pants. She was supposed to be the one that would be there for her sister, but now it was the other way around.
"Should we tell mom" asked Vanessa"
Allison's eyes widened again. What was she going to tell her mom? How would she do it? Dahlia was sharing a room with mom. How was she going to avoid her older sister's tormenting comments? Then again, with Vanessa's question, Did she even need to tell mom?